Please, please, talk to your music teacher, get a recommendation, and then go to a real music store. See what is available in the size you need. If this is a beginner project, ask about renting an instrument. It's a good way to start learning on a little bit of cash. Later you could purchase an instrument, when you know that the guitar study isn't just a passing phase.
If you buy a guitar at a toy store, you will be buying a toy guitar. I'm assuming you're not buying this for a toddler.
By the way, guitars, like violins and harps, are sensitive to heat, cold, and all sorts of other things. One of the first tasks a student learns to do is to tune it. Over and over! (There are inexpensive electronic devices that can help with the tuning.) I started learning to play guitar a couple of years ago. I'm probably better at the tuning part than anything else because I do it so much!