The only reason we were even considering buying into it now was because of the low resales and thinking it may be better to buy sooner rather than waiting for the inevitable.
I don't think it's inevitable that the resale prices will go up. Remember that the DVC contracts all have a deadline attached that will drive the price down over time. So I'm seconding Dean's belief that prices will not rise with inflation or even much as the TS market improves. Don't feel rushed!
Also, can you buy outright, or would you be borrowing? That's a significant price difference, and a significant difference in risk. If you own outright, renting out your points is a great resource right now. If you're still paying off your loan, renting out your points may not be enough to make up the difference.
I think you should try staying in a condo offsite and see how that works before you buy into DVC. A lot of people who go every year find they enjoy staying offsite and doing non-Disney things for part of their trip, especially as their kids get a bit older and start developing other interests. It may be that by the time your 7 yo hits nine or sometime shortly thereafter, the older kids will be lobbying for a Universal visit, meaning if you buy in for the then-3 yo, you could end up staying in DVC for a more "Orlando" vacation, which isn't ideal, IMHO. If you're not staying in the Disney bubble anyhow, why stay in the smaller DVC units?
I'd also look into renting points, either onsite or at the Wyndham Bonnet Creek resort (which is as close to the parks as most of the Value resorts, although of course you don't get Disney bus service or the
DDP). Whether you're going DVC or another TS, remember that you can do breakfast in your room so easily, and also other meals if so inclined, so the (possibly) higher per night room cost can be balanced out by the lower cost of food, especially if you have kids who may or may not eat their breakfast while on vacation anyhow.

Most of my kids at those ages did better eating breakfast cereal in the room without distractions than eating in any restaurant or hotel breakfast we tried, and so we didn't get the "ten o'clock starvies".
But I've also seen Wyndham Bonnet Creek prices where you'd be getting a full 2 BR condo for less than it cost that season for Disney Value resort rooms, just depends on when you go and what kind of rentals you can find. Definitely something to consider.
You could also stay off site some years, and rent DVC points from someone else some years, and come out ahead compared to buying into DVC. So there's some other possibilities to consider.

And, again, it's not like DVC resale prices are likely to skyrocket anytime soon. If you're fine with Value resorts, you'll be fine with DVC points at SSR or OKW, and those prices aren't likely to go up much in the next few years, and they're likely to be the last ones to rise so you'll have plenty of warning if it happens.