Hey! Welcome!
I'm about 5'9" I think, and really don't know how heavy I am. (If I don't know I can't get paranoid about it.) But take it for a run. I guarentee you'll either love it or hate it. I hope it's the first one....mainly so that if you meet up with us, I won't be the youngest one anymore...!
You won't fall over at lights, unless you've got a really long body and diddy legs. I'm about a 31" inside leg and have no problem reaching the floor. You just have to remember the pegs are not under your arse...
And don't worry we were all new at this at some point...

Some of us still don't know what we're doing.