My first rifle I built my own ar-15. I've had plenty of experience shooting 22lr, 20/12ga, 9mm 45acp, 38spl, 357, of course my .223 ar15, .308, and even 8mm Mauser, 30-30, 30-06. I am 17, so I can relate...
45 is harder to control, revolvers fired with consecutive trigger pulls take your aim off, so I'd rather get 2 9mm rnds in a target than one of the others. I'd rather have 10 .22 rounds than 2 45s up against a human. Now .45 costs 30cents per round and 9mm 25 Ish. .22lr is 10 cents, 223 is 30-40.
I suggest starting with a reliable defensive weapon like at/am/ glock pistol.
Pistols will help defend close areas in homes. Glock never fails, always fires, for 15,000 rounds straight no cleaning. One has fired 350k and is at a museum. The simple design with no safeties to hang up on, yet there as 3 safeties you bypass by pulling trigger, the trigger lock, firing pin lock, and "drop lock". Gen 4s have a loaded round indicatorindicator taken advantage of by the slide. All are loosely tolerant yet accurate. Used by cops round the globe.
Glocks are super light.
Bottom like the most reliable pistol is glock, other than those heavy revovlers. Ak is for rifle land. In both, if you replace extractors and what not every couple 1000 rounds, they can shoot steel.
The reason I built my ar was to get it before I couldn't, and to do it in my garage. I am going to move it out of state so I don't have to register. I went with delton mid length heavy bbl. I love the magpul 10/20 10/30 mags. I am OK with it, having shot less than 200 rounds. I put a primary arms cqb scope on it.
Secondly, I asked my legal guardian for the most reliable rimfire rifle in the world, ruger 10/22 and put nodak spud NDS 26 sights rail combo with an extended tech site front sight to save dough. Comes out to $360 because $260 after Paperwork. Plus $100 for sights.
I want to join the navy and get my residency in az then I'll get a glock 19, 17, 26, etc.