what the big deal mate!!!
but yeah its indeed surprising that she left a young guy like you for ur oldie uncle! must have seen something there, i believe money!!
however, i would suggest you to have faith in the Almighty God and be calm & maintain your coolness. just act as if nothing has gone wrong from your side and infact if you've enough guts then start giving those cheap and disgusting looks to your uncle for being such a jerk!!... n also if he tries to reveal some bull shit about you then u better than the lead n do the honor! :)