For a first gun, I'd say a modestly-priced striker fire is a good start. Just don't forget that there are other things out there and end up as some silly, confused Glock or XD or somesuch fanboy. Pref 9mm.
Next step up is a DA/SA 9mm. Preferably with a decocker.
9mm is cheap, easy to shoot, and actually useful in self-defense. If you go full-size steel, .45ACP should still be easy to control. But I wouldn't buy a 1911 as a first gun. 'Wonder nine' makes more sense, IMO.
And as safe as anyone will claim they 100% absolutely are, I'd still save guns of a higher caliber and/or trickier operation for a time when you have some experience and are very comfortable with something more plain-jane.
I've been posting in the big gun thread about getting into SA revolvers, and though I am still observing 'safe' practices, I notice how much more opportunity there if for one to blow their/someone's face off. Loading/unloading rounds one chamber at a time, needing to KNOW you've rotated the cylinder 360* before a gun has truly been 'cleared,' dick-fingering the hammer and letting it fall during cocking, ect. And to do some things efficiently, you really do need to violate safe range practices. Like how casings drop out a lot easier if you point the gun at the ceiling...
Anyway, my vote: 9mm and simple. You'll be happy with it. And then you'll buy more interesting stuff eventually.