Im only 14 and its hard to get my fingers all the way across the fretboard and press all of them down at once

Hello bluesman, I have short fingers and depending on the type of guitar and the neck width, I can have probs with 'grand barre' chords too. It would help to know what you're playing but short of that, you might try going to a music store and trying a few other guitars, especially those with a narrower neck.

GuitarZen

Or...., mostly just practice

this is a good question and a problem for many myself included i have played for years and after a short while my muscles begin to burn from doing song laden with barre chords. so the short answer unfourtunately is to get tough. at least in my exp. guitar zen is always right ( in my opinion ) which will make him laugh. a guality guitar makes all the difference in the world for playing guitars one that frets easily is a key to being able to form nice sounding guitar chords especially barre chords. the unfortunate part is that they are not cheap.
that being said i always practice with a guitar that has hard action on it so when i play a sweet guitar  with nice action it seems much easier to me.
or in other words playing on an acoustic will help you get the strength you need and when and if you pick up an electric it will seem much easier i think most will agree.

yeah cricketriders right.

an acoustic is 'harder' to play in that the string are tougher.
so playing an acoustic will strengthen your fingers more than an electric would.

A couple things you can also do if you have not done them already: 1)using a lighter gage of strings 2)lowering the bridge

http://www.guitarmore.com/

Scott's right...except its a little more involved than that. 2 things affect how hard it is to finger a note, the relief of the neck and the action of the bridge. from 1st fret to 8th fret your neck should bow away from the strings less than the thickness of a credit card. If it bows more then fingering notes will be difficult, if its bowed the opposite direction then your strings will rattle on the frets. Next your bridge should be as low as it can go without fret buzz occurring. If its still hard to press down the strings after those adjustments are made then tune down 1/2 step or a whole step or 2 whole steps, whatever. Unless your playing a steel stringed acoustic, fretting notes and chords should take hardly any effort.

bluesman76 wrote:

Im only 14 and its hard to get my fingers all the way across the fretboard and press all of them down at once

I've found that establishing rhythm with barre chords helps.  In other words, relax your finders (especially the barre) with the beat to let your muscles flex.

A Good way to solve that is to practice playing them higher on the neck like at the 5 and 7th fret and slowy work your way down till you can play them at the first fret and you also may want to try working on smaller bar chords that only involve 4 or 5 strings  (p.s. dont worry im 15 and have small hands too)

hope that helps