Love the enthusiasm. Keep it up. And welcome to Divebuddy.
As for "must have" equipment...let’s see...this would be just my opinion of course. I love my Apollo Bio Fins (split fins), but the most important part is the spring straps. A must have for sure. Easy on and off, plus they never break and ruin your day. Split fins are nice if you have a tendacy to get leg cramps like me. The also help with your air consumption by requiring less energy. Get a good dive light, and I recommend one with a rechargeable cell instead of using expensive C or D cells. As for a BCD, I went with the Dive Rite transpac with travel wing because it is extremely durable, streamlined, and packs really small for the dive trips. But if comfort is your most important issue, the best I personally ever rented and loved (but never bought) was the Seaquest Balance. I would recommend renting a few different so see which you like the most. For a reg I went with the Atomic B2 Reg and Atomic SS1 integrated octo/inflator. I bought these for two reasons; highly rated in reviews as top of the line, plus you only need to service every two years. I’m lazy about servicing so I liked this befefit. Other brands offered free lifetime replacement parts (not labor), but you still need to service every year. I also like my SS1 because it breaths as good as my main reg, and it easily unscrews from the end of the inflator hose which I can screw in my garden hose for easy cleaning. For a computer, there are many brands depending on the amount of money you want to spend. I haven’t tried enough of them to really say one is better than another in all fairness. But what I can recommend is to go hoseless with a transmitter to your wrist-watch computer. It’s so nice to just flick your wrist over to check your air, instead of fishing around on your side for your computer. Plus one less hose to worry about. Careful....once you try this it’s hard to go back! Okay, have I spent all your money yet? ;-)
Hope this helps. You will get a big variety of opinions over the next few days. Dive safe and stay wet!