Okay..you've gotten a couple of good answers so far, but you need to weigh a couple of factors. Where in DC is your job actually going to be located. That as well as your budget for cost of living will make a HUGE impact on hwre you would like to live. So first let me address Severn.
I am sure you looked at this area because it is "cheaper" than some other areas. Not to disuade you, but it is the location of a couple of detention centers (prisons), so property values are not what they could be. It is also one of the host areas for the National Security Agency...Laurel is on the other side as well as a little town called Odenton. They are not what I would call great areas fro someone new to the area. After you have been here for awahile, your attitude may change, but the commute from that area (down the BW Parkway...295) is not the most fun in the area.
As both have mentioned, you should probaly look in Arlington, Fairfax (VA) or Montgomery (MD) counties in the area for the best schools and a somewhat easier commute. I will warn you that Fairfax County is the richest county in the nation and you do get what you pay for. Easy access to metro and some of the best schools in the country. It also has one of the highest costs of living. However, can you put a price on the your peice of mind as a single parent for your safety and convenience?
I lived in Laurel many years ago and currently live in Fairfax County.....LOVE it!