At your age you could be in the upper ranges of testosterone naturally, then again you may not be. At 300mg a week some guys would have supra-physiological levels and some guys will be just elevated. Can you run labs before you start… TT, Free T, E2, SHBG, FSH, LH?
You don’t need that much adex or any at all for that matter. With regard to the dbol its a great kick starter and your call. I think most guys here would tell you to run test only for your first go about but I don’t see anything wrong with it.
A pic for evaluation would be good. Its highly doubtful, you have met your genetic potential.
There are a shit ton of threads in here with young guys asking for help. It would be a good idea for you to read them before deciding what you want to do.