Advice on grip/feel

New shooter here, been to the range a few times and have been trying the like the P365 Xmacro but feel the grip may not be filling enough for my hands. Is the knuckle of your trigger finger supposed to be flush on the grip or can you get away with it being off the grip?

I don't have big hands by any means either just probably nitpicking. Just some pointers would be appreciated.