Thanks everyone,

I ordered 18" and it was a good choice. I took her (bike is her or him??) for a ride and it was very nice.
I need to adjust the "knee" in the handlebar, can you tell me which allen key size I need?

BTW, since next month starts 2014 models you can get a good deal on the Venture 4.0; I paid $380 + tax of course - Burbank, CA