I would definitely keep the old Kenmore. I posted my story about this here before and on a sewing forum, about how I ended up buying my same model old machine a I understood the value of what I stupidly tossed away.
Here it is:
I had an old Kenmore sewing machine that I had learned to sew on, from back in the '70s. I used to sew on it all the time. I loved sewing.
One day, about 6 years ago the motor caught fire.
Instead of replacing the motor, I tossed it out, thinking I was upgrading and got a brand new Sears/Janome electronic machine with many fancy stitches & perks, but didn't realize it is a "starter machine."
NEVER BUY WHAT IS CALLED A STARTER MACHINE! My old machine was so basic, I never even knew there was such a thing -- that a machine could have LESS features???
This machine had no adjustable pressure presser foot (can't be replaced,) and barely has the horsepower to sew through three layers of a medium weight material (which is a folded over hem. No heavyweight materials or thick multiple layers, as the machine jams when going over heavy seams - like when the folded hem lays over the side seam. I couldn't even hand turn the handwheel, to gently, manually coax the needle through thick seams as the electronic mechanism inside would jam.
Forget sewing denim jeans: raising hems or lowering the waistbands on high-waisted jeans which have the most folded material (5 layers, not including going over side seams.)
Or sewing thick winter-weight knits, coat-weight wools & bulky fleece - which is the climate I live in. The presser foot pressure wouldn't adjust for the extra bulk.
Apparently a "starter machine" is only used to sew lightweight materials. Right! Like that's real life sewing. Not!
I so LOATHED sewing on that machine that I have barely sewed anything, even basic repairs, in the last several YEARS since I got that machine.
Had I known what I know now, I would never have tossed out that old Kenmore machine to "upgrade." I would have replaced the motor. It was a workhorse.
All metal parts. Didn't have fancy stitching, just zig-zag and blind hem and I could make decent buttonholes. Yet, I sewed like crazy with it.
So, I went on the hunt to replace that old machine with the same exact model, so I don't get any more unpleasant surprises with a different model. It did
everything I NEEDED.
Turns out these old, vintage machines are actually quite popular and selling like hotcakes all over eBay & Craigslist as many other people realize the ALL METAL quality is much better than the newer, cheaper, plastic and electronic models. I finally found the old Kenmore machine several weeks ago in amazingly excellent condition. I got it at a steal price. It just needed a simple tune up to fix the timing.
But, that is so much cheaper than buying a newer and lesser quality machine, as another sewer on a sewing forum made me realize this machine, with parts that won't wear out as quickly as the newer plastic models, is an INVESTMENT. This machine will probably last my lifetime.
It's like coming home to an old lover.
I have been sewing quite a bit again, making alterations, repairs, and upcycling/refashioning clothes into totally different looks. I have a pile of projects, including home furnishings & accessories I can't wait to get into. I have been visiting many sewing sites looking for new ideas. I love sewing again. I love having clothes that fit again.
There are also many new types of fancy presser feet attachments that I can put on my machine to do different techniques that were hard to do manually before. Different types of presser feet is different than an
adjustable pressure presser foot. The different types of presser feet is an accessory one can snap/screw on & off. An
adjustable pressure presser foot is a
rod inside the machine and can't be removed. The pressure can be changed by changing a dial or pushing a knob in the rod. It changes the HEIGHT and pressure of the presser feet according to the thickness of the materials one is sewing. Do NOT let some idiot at the store tell you they are now "automatic," and has no no manual override feature. All that is, is a metal spring and it is NOT automatic. Your DD will end up with the same problem I had and probably stop sewing, too. I know several people who sold their same Janome machine I had, a couple years later as they also found that machine so limiting.
My suggestion is to take that old Kemore machine with the ALL METAL PARTS. Skip a lot of the fancy bells & whistles and go for the basic features she will NEED to sew a variety of items; straight stitch, zig-zag, a couple hemming stitches, buttonholing, an
adjustable pressure presser foot, and then she can buy several different snap-on presser feet to add on over time, as she learns to sew different things.
Fancy stitches are a nice perk, as well as an automatic needle threader, auto-buttonholer, but not necessary. If you skimp on the
basics in the last paragraph, there is no point in sewing with that machine. If she wants fancy stitches, she can always sew on lace, embroidery trims and appliques as embellishments.
Learning to sew on what you now think is a more "complicated machine" means any techniques she learns afterwards will only get
easier. I can sew a buttonhole manually. I will never be stuck if the auto-buttonholer mechanism on a computerized machine stops functioning correctly. I can pretty much thread almost any machine anywhere, as I properly leaned how and don't rely on a button to automatically thread for me.
Here is a pic or my "new-to-me" old lover come back home:
NO plastic breakable parts ANYWHERE!
In my second picture, you can see the silver bobbin casing on the left, under the machine. (Access plate in the top pic.) Once DD knows how to put in the bobbin, and practices a few times, it becomes automatic to slide it in. I never give it a second thought. I can change a bobbin in my sleep. 
If it's just been serviced and in good condition, you can probably get $100 - $150 for it.
I wouldn't have ended up with the Janome I have. But, really, I thought any new model in this century had to be better than what I had. 
