This thread reminds me of a bunch of kids jumping up and down yelling ME,ME,ME!!!!
9mm has more energy than a 38 special, so what, they both work about as well on a threat. A 357 magnum fired from the same gun as the 38 beats both of them.
Go to a good gun store, what feels better in your hand? My suggestion for a first gun is a quality revolver, I am partial to Smith and Wesson's myself.
The reason I say revolver is an easier manual of arms. If you want an auto I would say Glock 17/19 they are like the ever-ready bunny of guns.
The bottom line is YOU have to be happy with your purchase.
Either way get some quality training.
My rifle and pistol are tools, I am the weapon.