I'd start off with a small simple DA only revolver or pistol then move up to a larger caliber(.45acp, .44spl, .357magnum)...
A stainless steel Ruger SP101 .357magnum revolver(5 shot, DA only) or a LCR(.357magnum) can help you learn the basics. These snub revolvers or a S&W model 442/638/642 .38spl are small, lightweight & can be ordered with a bright lasergrip:
www.crimsontrace.com .
A DA only pistol like a SIG P239 DAK or a P290 may help but I'd buy a new revolver first.
You can buy a .45acp or a .357sig(my first choice for a defense caliber).
For top defense ammunition, see; Corbon, Speer Gold Dot, Ranger T/T Series, Golden Saber, Hornady(Critical Duty).
Only use factory rounds for a carry-defense weapon; NO reloads or hand loaded ammunition. Clean & inspect your pistol often too. Dust, grit, crud, etc can damage a carry pistol.
Get skill training & join the NRA too,
www.NRA.org . They work to protect your 2A rights.
Clyde