I think a PPS in 9mm is a great first carry gun. Just rent one first and see what you think. The slimness of the gun makes a huge difference IMO. Just be sure to do the checklist.
-Is 7 or 8 rounds enough for you? 7 rounds with one spare mag is enough for me, but everyone is different,
-Is your wife/girlfriend going to have to be able to shoot it? Can she pull the slide back?
-The PPS has the lever mag release. Its a simple thing to get used to, but some hate it.
-Make sure the "no safety" will not prevent you from carrying with one in the chamber. I wanted a safety when I first started carrying, but now understand that the holster is the safety and I would not want a safety on a striker fired gun.
I bought the XD9SC for my first carry gun. Its a bit wide for me. I like to carry at 3 oclock and OWB. The PPS is slim enough that I can carry at 3 oclock without searching for a certain type of shirt. I dont like carrying at 4 or 5 oclock, because it seems like im always leaning against or sitting on the gun. My car seats really wrap around my back, so its uncomfortable. But, I have pain in my low back and hip from nerve damage, so it probably doesnt bother most people. Buy a large gun, and it may not get carried as much, and buying a tiny 45 or even 40 may cause you to lose accuracy. I also think that the 9mm is the perfect first carry gun. Im only pushing the PPS because you were thinking about it already. ok...thats enough rambling...good luck