Anonymous wrote:OP, you should definitely stay put where you are, until the baby gets there and you know what the life as a parent is like for you. Don't make a decision now to buy a condo, because a few years down the line you may think differently and want a detached home. Living in an apartment with kids is definitely doable and can be great, but it's not for everyone, even those who lived in apartments for many years as single adults and loved it.
DC is a bit different from NYC as far as discrepancy between the rent and ownership is concerned. In desirable areas such as yours, the rents are very high and often can be the same as the mortgage would be. 500 a month difference is not as significant as let's say in Manhattan, where it would be more like 2-3K a month. So, when you are paying rent here, you might actually be paying a mortgage on a place that is similar in the same amount as your rent. so, if you definitely knew what type of housing and area you wanted, I would say, buy as you won't be saving much by renting. But, if you are still TTC and have no idea what your needs and desires may be after the baby arrives, I'd say wait.
Also, forgot to mention, think that the rent can up too over the years. I am not sure what arrangement you have, there might be some ceiling on your rent, but if there isn't and there is no rent control of any kind, your rent can eventually become more than what you bargained for. In NYC, that is one of the main reasons people choose to buy and commit to paying 2K a month more to have a similar apartment, because they are scared what their rents will be like 10 years from now when not in a rent stabilized unit.
Not saying you should buy now as you are obviously not ready, but don't wait for 10 years, as your rent could easily surpass what your mortgage would have been and you would have not saved much and would have nothing to show for it.