I am overhauling my laundry room. As a result I have the walls and ceilings gutted. This gives me easier access to run wiring to other parts of the house. This spring/summer I want to have an attic exhaust fan added. One wire I run will power 1-2 roof fans. The other will power lights in the attic and two outlets in bedrooms. The power that goes to the outlets currently will be switched to ceiling fans. I currently have 14/2 Romex wire. Should I use 14 or 12 for the attic fans?

I am a novice at this all...learning on the job.

You can run 12 wire for the fan. As long as the fan your talking about is one of those roof mounted or gable mounted ones. If your thinking of something else you need to check the size of the motors.

Over sizing the wire is not a bad thing. Under sizing after the fact becomes expensive to fix later.

Check with the local code office. They may have a special requirement for the fan. Ideally it should be on its own breaker.

Also if you have two attics. Use two fans. One attic one fan. You do not want more then one fan per attic space. Be sure to wire in a de-humidistat when connecting the fan(s) Otherwise you will suffer a mold issue in a few years.
Most fans now come with them already installed with the temp stat as well.

Now is certainly the time to plan for future wiring needs. just a few comments. As a rule, 14 gauge wire can be fused at 15 amps. 12 gauge at 20 amps. I agree that the fans should have their own breaker rated at whatever the total draw is for the fans with a little bit of margine for inrush draw on start up. Lighting is generally run on 14 gauge wire and should be on a separate circuit from the receptacles. The receps should be run on 12 gauge and fused for 20 amps. Code now requires that bedroom receptacles be fed by an arc flash circuit interupting breaker (AFCI). Lights should not be mixed with receptacles on circuits because if the breaker trips you are now in the dark, plus lighting fixtures are not always wired heavy enough to be incorporated into a 20 amp circuit. Just curious as to why you don't leave the receptacle circuit alone and run a new feed for the ceiling fans??? The attic lights and ceiling fans should run on a single circuit saving you an AFCI breaker and a wire run.

I am very new to home remodeling. I was planning on switching the wiring because right now there is no over head light. I was going to take the wire that the switch currently controls for the fan. I could simply allow an electrician to run the wiring for me down the road but I feel that I can install this myself.

I don't blame you for doing as much as possible yourself. I would run an extra wire from the panel to the attic space while you can for anything that you may need in the future. Leave it coiled up at both ends, cause you just never know. Since you are overhauling a laundry room, now is a good time to be upgrading the electric to that space as well. Washers are now supposed to be on a dedicated circuit, so if it isn't already and you have room in your panel, I would do that as well. Good Luck.