I am in the same boat as you! Mine are 12 and 10 and just got on skis. They are hooked, and we are trying to get in as much as we can this winter.
We went to Whitetail last Monday (Jan 26th). Conditions are great.
Whitetail has a great beginner area that is away from the rest of the crowds with its own lift. If your sons make it through that, and are ready to graduate, their easier slopes are nice and big and wide, again, served by their own lift.
The one down-side to Whitetail is the two main lifts are back to back, so the crowd conglomerates in one area. If you have a beginner coming down the hill and then trying to get into the lift area, it is easy to crash into people. I wouldn't move out of the bunny slope area until you are sure they can stop and control themselves well.
I don't have any advise for you regarding schools. We chose DIY lessons, and my boys being quite athletic too, took right to it.
To drive to Whitetail if you choose to go there, head out to Winchester on 7, and then up 81 to Clear Spring. It will probably take you less than an hour and a half.
BTW, if they are hooked, and you want to get them equipment, I found this amazing shop in Chantilly near my office. They deal in a lot of gently-used kids stuff and have a much better selection and better deals than Ski Chalet. I was able to get Skis, boots, poles for both boys for about $250. NICE stuff too...K2s, Rossignol, Solomon. The Rossies were brand new. If you are going to ski a lot, it is a lot cheaper then renting, and they will do exchanges next season. Place is Extreme Allsport at 4008 C Walney Rd, Chantilly. 703-449-9700. Pete, the owner is a great guy.