No you should not. There's a chance of you falling and hurting yourself and baby .
I personally wouldnt but maybe call L&D and see if they cant connect you to an on call dr to ask. They do that for me here. Since they say if you rode horses before getting pregnant then you can during pregnancy and the same risk factors ie falling or injury seem to be about the same I wouldnt really know how to advise.
If you snowboard when not pregnant and are generally athletic, there is no reason not to snowboard at only 7 weeks. As Lady says, the general advice from doctors is that it's safe to keep doing the same kind of athletics your body is used to doing. Some women lift or run or do the Ironman while pregnant. One of the beach volleyball women won her gold medal in the Olympics when pregnant, and several divers have. The baby is teeny tiny at 7 weeks, I think the size of a walnut or something, cushioned in a sac of liquid and surrounded by the muscles of the uterus and your body. You aren't going to hurt the baby even if you fall down.