Your sister gave good advice. And dont worry about the fitting. when I did my first one, I just told the guy to set it up how he thought it should be. then I would adapt. that way I assumed (and it worked) that if I had pains, I would simply have to ride enough for them to go away.

they did go away. My hands would go numb in about 10 minutes at first, and my but hurt like no tomorrow. It all got better. My hands still get numb on long climbs but it doesnt matter, I just take one hand, hold it down, and shake for 30 seconds and its all good again.

Just go ride, and have a good time...dont start trying to adjust everything or buy all new parts until you do realize what it is supposed to feel like.