Not trying to hate on you, but when I was 18 I was 5'6" 138 and by my 20th birthday I was 5'6" 178. I know you want to get big and you'll probably run a cycle no matter what we say so I'll try to answer your questions to the best of my ability. Dbol and test is a routine basic cycle.
When I first ran test I did test cypionate 400mg a week for 12 weeks. Arimidex is an aromatase inhibitor. Clomid is fine for pct but I personally use Nolva at 40/20/20/20 after a test only cycle. And on test you shouldn't have any sexual dysfunction but it does happen on some occasions, everyone is different.