We rented for 5 years. That was at the time that "everyone" was buying- so rent was cheap (for DC). When we moved out of our 2bdrm 2.5 bth penthouse, it was when everyone started renting and WE were buying. They raised our rent for the new renter by $1000/month. Yep, $1000/month increase. We bought at the bottom. We have a 2200 sf home for less than what the apartment now charges. Had the market not hit bottom, though, we would have never bought here.
It's all about timing.

bought (again) in '07 after many yrs in another house ... want more room but we're renovating/adding rather than buying ...

No reason to rush into buying IMO til you see what's right for you, though it shocks me that rent on a 2 BR apt. in Ballston/Clarendon is as much/more than the mortgage payment on our 2100 SF house on a 10,000 SF lot in a nice wooded area.

We're with you OP. Also from NYC. Big difference is that most schools in DC are far below NYC standards. I would never buy in DC unless I planned to homeschool or send kids to private school.

I think it comes down to personal values. I've been trying to educate myself about home ownership and feeling like I was missing out on something if I did not buy. But eventually I realized that 1) I am too risk-averse. The idea of sinking all my savings into a single investment that may or may not appreciate and going from 0 to 300,000 in debt is simply not attractive at all. 2) I am a commitment-phobe. I like knowing that I could easily pick up and move if my job, my daughter's school, my relationship status, or anything else were to change tomorrow. 3) Proximity to public transportation and public play spaces is much more important than having your own yard, especially with a single child who needs others to play with or else she neds up sitting in her room all day playing video games. 4) I am simply too lazy to deal with repairs, mortgage, taxes, etc.

OP, you can't compare rent vs. mortgage, taxes, insurance. You also have to look at what you'd save in income taxes deductions and the amount of principal you'd pay down each month. My PITI is about 4k/month, but I save about $900/month in reduced income tax because I can deduct mortgage interest and property taxes. Plus, I pay down my principal by hundreds of dollars a month. So the price of owning my home is at least $1500/month less than renting a comparable home, and is on par with renting a small 2 bedroom apartment without amenities.

You should rent when you are ready, not when your mother (or MIL) wants you to rent. You are recent transplants. You should wait until you know more about the city and the area where you might want to buy. Learn about how your lives and jobs go here in this area. Find out what works and what doesn't for you. Figure out where you want your children to go to school and so many other issues that will affect your lives. Your mothers do not have to live your lives, your commutes, your family issues, you do.

I think, for you, buying now would be a mistake. We all make some educated and some arbitrary decisions in choosing a home. Increasing the educated decisions and minimizing the arbitrary ones can only help you find a home well suited to your family. Give yourselves time.

OP, we too relocated here, and rented for 18 months.
The area is expensive. But it is worth it to wait and see where you really want to live. We likewise did NOT move far out, to get the bigger house and land. The commutes here are killer.