Those guys with the long, slender, nimble fingers probably have an advantage over us short, stubby-fingered guys, but that doesn't mean we can't play. When I was younger, I had a couple of teachers refuse to give me lessons and tell me to hang it up because my hands were too small. (One even told me he wouldn't take a student that couldn't wrap his hand around the neck and touch thumb to fingertip on every finger at the widest part of the neck.) Luckily, I was a stubborn little cuss, so I made it a goal to prove them both wrong. I'm not a good player by any means, but I can play, and I've improved steadily since I've started taking the lessons here.

BrokenJera gave you some good advice on the pressure. Think about your shooting experience. It's a bit like shooting a rifle, if you jerk the trigger hard, you're going to pull the shot off target. If you squeeze it off gently, the shot goes right where you want it, and you don't have to reset as much for the next shot (or chord). You only need to use as much pressure as it takes to give you a clear note.

I started learning on an electric, and didn't pick up an acoustic until later. A lot of people recommend that you start learning on an acoustic because it's a little more difficult to play and its hard to hide your mistakes. Some of the instructors here may disagree with me, but I think you should play what you're more comfortable playing. The more you enjoy it, the more you'll play and the better you'll get. I like to play acoustic, but I love to play electric. Either way, make sure you've got a good comfortable action on your strings. A high action can be part of the problem if you're pressing too hard.

F is a pain. I don't know that anyone ever really gets comfortable playing it. :D The only advice I can give you there is play it and play it and play it and play it until your fingers start to recognize it.