I’m going to be quite frank, but in no way judgmental; you are far & away (by all known metrics) very large. I guarantee you that most people you show a 7.2" penis to will believe it’s 8 or 9 inches, and you are well within the Magnum XL range for Condoms.
So as conventional wisdom would have it: "if it ain’t broke, don’t fix it." Whether it is manual penis enlargement (PE) exercises and/or elective surgical/non-surgical enhancement, they aren’t without risk. If you were under-average, I would have said your 20’s would be a great time to do it since your body just heals better and you’re approaching your physical prime. However, given what you have now, I would just enjoy it for all your 20s and revisit this question again in your 30s.
This way you can really know if your desire to obtain freakish dimensions isn’t just something influenced by an oversexualized society, porn consumption, and/or immaturity (and I say that respectfully, I mean in terms of not having really experienced your sex life with an already endowed penis, and that in later years you won’t look back and scratch your head on why you ever considered this in the first place).
Whether manual PE exercises (pumping, hanging, stretching, extending, jelqing, clamping, etc.) or male phalloplasty (injections, graft implants, etc.), all of these endeavors come with risk of injury and/or complication. It would be a tragedy to see someone with a perfectly good and undeniably large penis end up breaking it because of unfounded/non-existent/falsely-perceived shortcomings.
I would say wait it out till AT LEAST 30, if not 35. Unless you plan to become an adult actor (or live an "alternative lifestyle"), this PE adventure is not worthwhile at your age & size (in my opinion). And again, without trying to sound judgmental, why not put the kind of focus that is required to see PE through into areas of life where you may find more fulfillment in (examples: a new hobby, career ambitions, fitness goals, etc.). Improve areas that might be genuinely lacking instead; you’re already hung, so why not work on getting wealthier, getting smarter, getting stronger, better dressed, or any other aspect of what makes you more sexually attractive or desirable?