When I was a child I never learned how to ride a bike. I am now in my early 20s and would like to finally learn. I am pretty athletic and am confident that I will pick it up pretty quickly, but need some advice on which bike I should buy. I am 5'7" and am probably done growing. I am definately a novice and would like a bike that I can learn on, but also keep for a long time. Would also like to buy a bike at a good value. Can anyone give me advice on which sized bike I should buy (I think I will need the tire size) and any tips you have on learning to ride?

Thank You!