I was 12 and I saved my snow shoveling and grass cutting for a .410 from Sears. Dad took me hunting and I got my first 2 pheasants that day....great memories.
22 when I bought my first rifle. It was a Plainfield M1 carbine with telescoping wire stock. It was used and I couldn't get 3 rounds through it with a FTF or a stove pipe. Dis my first gun smithing on it with a hand file. Could dump 30 rounds without issue. (most of the time)
24 when I bought my first hand gun. Moving to western PA from Louisiana when the moving guy spooked me. He told me people in west PA were strange (I had never been east before). On my way to PA, I stopped in Shreveport La and bought a S&W Model 39 and box of cartridges (he didn't have a 1911 and the 59 was too fat for my hand). I had to show an ID, something my address on it (electric bill) and say I had never been convicted of a felony. Took less than 20 minutes and I was out the door.
Sold them both to feed my kid when I got divorced. Years later, I told him about it. He said I should have kept them, he would have rather been hungry.
The first one bought with my own money was at 14: a Hawken .50 out of Sportsman's Guide. Shot at many a rendezvous with it (won quite a few shoots with it, too!) I already had a .22 and .270 as Xmas/Bday gifts to hunt rabbits and bigger critters with.
18. Bought a Ruger 10/22 Carbine with the standard wood stock (I think that was the only model available back then) in 1986 from Best Products. Think it was $130.
I guess I hold the record :-) I was 70 years old and looking for something to do. I took an NRA basic pistol course and the instructor's personal gun was a Kimber. So I bought one. Still my favorite sidearm.
With the fervor of a convert I've bought about 10 other guns and am now an FFL
Father in law gave me a S&W 357 revolver shortly after I married his daughter at 19. I never bought anything on my own till I was nearly 30 and moved to rural property where I knew it would be a good idea to keep a 12GA handy for any bothersome critters that needed dealing with. I bought a Winchester 1300.