It would definitely be to see how I can handle it...as in handling being w the girls 24/7 and seeing if they will listen to me, especially the 9 year old. I never thought about not handling the curriculum. I am college educated, I have a Masters Degree. Sure I would have to relearn some things I have not done in years (like trig) but to my knowledge lots of homeschoolers do not have college degrees and they educate their children just fine. As for foreign language, I am sure something like using Rosetta Stone is better than HS Spanish. I took Spanish from 7th to 10th grade and 1 year in college and I cant speak Spanish at all! And yes I received A's in those classes.
It sounds like you will do fine - but honestly, a LOT of homeschoolers don't do fine because they don't have the skills. Spend some time with real homeschoolers (instead of people talking about the perfection you get on the internet) and you'll discover a lot of people like my sister in law - who didn't manage to get her son through high school not because she didn't try or didn't have an education herself - but because he's a special needs kid and it took her a long time to figure out how to meet his needs. (He finished his GED at 22 - through the public school system). Lots of those kids aren't the ones you hear about doing great on college acceptance, because they don't go to college and never take the SAT or ACT - and because parents self report - you tend to hear successes and not failures. Teaching something is different than knowing it - I was a statistician for a while, and teaching Algebra is not easy. I went the Rosetta Stone route and it didn't work well at all - its taught for conversational Spanish for adults, which is a whole different thing than being able to pass a test for fluency for college. And since you aren't accredited, they will need to test (where the public school they probably won't). We ended up dropping Spanish and doing two years of math in a year.
Since you need to think long term, here is what I would ask yourself.
Do you want a curriculum or are you going to teach freestyle? Both have advantages and disadvantages - a curriculum can be modified to be more freestyle but gives you something to work from.
The two extremes are probably unschooling at one end and a classical education at the other - but it isn't really a continuum.
What's your educational philosophy. I like worksheets, it gives me a measurement system. As someone said up above, that sounds like hell to them, but I had a kid who was homeschooled for discipline - we needed structure and a measurement system. He was also reintegrating into public school, so we needed to cover a certain amount of material in a certain amount of time. My daughter's friend is homeschooled, but is very autodiadatic - her mother doesn't need to do much than get her to the library. She'll reintegrate for high school because they can't give her the Science at home she needs - but she's already tested far above grade level for Math and English. That's a very different kid than mine. (My daughter would be far easier to homeschool - I'd just need to keep her pointed at a target so she didn't lose herself in reading and actually keep up with Math - but she'll self teach).
What are your state regulations - ours aren't much and are pretty easy to get through.
If you want a curriculum, do you want secular or Christian (there might be other religious curriculum out there, but most of them are Christian).
What is the availability of coop learning that matches your educational philosophy. My daughter's friend was pulled from her homeschool coop since it was not an improvement over the bullying situation that she was pulled from public school for (she's a strange kid).
What are your backup plans - if Rosetta Stone doesn't work for you. If you need to go back to work because your husband gets ill or loses his job or leaves you. If they get to high school and you discover that you can't adequately cover high school level material at home.
How responsive are your kids to you - I have a friend who tried to homeschool her daughter - it wasn't the best situation since her daughter and her at that point were in the middle of a head butting contest. She was far more responsive to teachers than to mom (middle school can be like that).
I loved homeschooling, it was a great year and I'm really glad I did it - but I got cornered into it - and there were a lot of mistakes I made because I didn't get the opportunity you have to think it through.