Recently purchased a Ruger SR40...like the SR9 as well...for a smaller version check out the LC9 or LCR and LCP versions. Reasanably priced, very reliable.
Also...attend some training classes if this is all new to you, as it is for me, I’ve attended three courses so far and look forward to a few more. Various instructors have varying ideas...go in with an open mind and learn all you can.
The NRA is a valuable source as well.
Go with a Glock 17 or 19. I’ve had a 17 for over 15 years and still enjoy shooting it, despite the fact that I have several others to choose from.
I recently got a couple other Glocks, just because I’ve been so happy with this one.
Light, inexpensive, lots of accessories available, ammo is cheap (relatively) and pretty much foolproof.
I think for the money, you can’t beat a Ruger.