Bro I have bin training on and off for 12 years I started when I was 16 years old.
I never even thought about Gear till I was 25 because I didn't wont to screw up all my natural Test and other shit that go's with it.
I didn't know the 1st thing about bodybuilding till about 20 or 21, I never thought that all 80% of it was Diet even If you where taking gear with out a good diet it will not do shit for you bro.
Next you need a good training regimen, Mine is 3 days a week 30 min. a day and cardio on my off days...
Bro I was a small framed dude when I was younger, like 180ibs. By the Time I ran my 1st cycle of gear I was 215ibs at 10% BF, so I hit this goal clean with a good diet and training regimen...
Once you build a frame then you can think about it but you better have all and everything in check bro, including your brain because one wrong thing happens and you will not know what to do.........
Read up a lil before you do something you will regret, and by the way them pros are like 35 to 40 years old and have bin training for the last 20 years homey.......
pz
take care and good luck.................