Don't over think it. Get some good (that does not mean expensive) cycling clothing and get out and put some miles on!

Good idea on the pedals.

So here's your check list:

Pedals
Helmet
Bibs
Jersey
Sunglasses
Shoes (not necessary at first, but you'll probably want to get some at some point)
Bottle cages (if you don't already have some)
Water bottles
Seat pack (containing: patches; multi tool; tire levers; Co2 (or get a mini pump))