You will probably ask me to define “well,” but to be honest, I don’t really know.
I guess I’m just curious how long it takes to be able to switch between chords, and learn a song, and learn to strum well.
I am a girl who can learn fairly fast, and can be very musical. I am thinking of starting to learn guitar.
Hey! You go girl! Haha, I'm a female guitarist as well, and I don't regret starting a bit.
The rewards of being a girl guitarist are endless. Everyone thinks it's amazing, even if you don't play very well.
I've been playing for about 2 years, practicing just about every day. But it isn't tedious work and it never was.
Whenever you're bored, on the computer of what not, just make sure you have the guitar in your lap.
The sooner your fingers callus, the easier the playing will be. It never hurt that bad, but sometimes the pressure of the strings can irritate the fingers. I recommend playing straight out of the shower, when the skin on your fingers is very tender. It'll hurt at the time, but the skin will strengthen quicker this way.
I give guitar lessons and usually after about two 1 hour sessions, I can have a student playing a song. The first song I usually teach is You and Me by Lifehouse; a song with about 10 movable chords. The changing of the chords is the hardest part, not the actual finger configuration. I've never taken lessons, but I did have a book. It was basic and came with my guitar. I cannot read music, but I can read tablature. If you don't know exactly what I'm talking about, you'll learn 
With practice, I bet you'll have a song or two down within the first month. I know this sounds lame, but you really can't give up. Don't expect to be amazing when you start. Even Hendrix sucked at a time, so don't get down on yourself.
I really encourage you to learn; the rewards are endless. Seriously.
If you want to know what a guitar sounds like after about 2 years of dedicated learning, check out some of my YouTube videos if you want.
http://www.youtube.com/user/KellyIsMusical
The Best of Luck to you!!
Great choice with the Guitar.