People have already said everything. Look into python, theres a tutorial by SciDave on it and its pretty good. I found it a bit too frustrating so I started looking into Unity. But its certainly possible.
Also, I think there's a lot of unhelpful comments here. Maybe the original poster should have said "is it possible to program an MMO in construct". Lots of people seem to think he's asking "can i make WoW?". Not all MMOs need to have 9,000 quests and 27 hours of music.
Anyway, good luck. sounds fun