Buying a "school uniform" is not a big deal... even thou you need to buy shoes, socks, sport shoes and two sets of pants or skirts and shirts, so one set can be worn while the other is being washed.
The bigger deal may be, that YOU will want to see her GOING to school IF you buy her any stuff for it, don't you?
Does she have the books and supplies? Does she have the money for the bus or concho ride? Can her family give her a sandwich and juice along so she won't starve during the break? Probably not because just the books and supplies cost more than the uniform.
Or are you ready to pick up on all the above too?
She might be going to public school and then, once you look at what she is or can be learning there, you might also ask yourself it is worth the cost of an uniform and wonder IF at all doing something, you'd better want to do something meaningful and put her into a school which can still give her a CHANCE in life (doesn't HAVE to be academic... but at least geared towards a real profession).
At 14 some of the local girls find themselves one year short of believing to be a WOMAN, with a whole different status and also the impression of knowing it all and having some more rights about taking decision... Would she embrace any CHANCE you would offer her? 14 can be a stupid age...
What should you do? I can't say. But I think you should follow your heart but not excluding what your brain commands you. IF you choose to consider to take the step, first build up a relationship with the girl in question and see if she is genuinely interested in give her all for a better future. If not, you may soon feel like you threw money at a fire and it may deteriorate your relationship with your employee.
NEVER offer money, NEVER give them money so they can pay for such and such. YOU will NEED to take control of the whole process and dedicate time, again IF you choose to do it.
When paying for it ALL (a decent school which only makes about less than half of the total, books, after school home work classes unless you can dedicate the time, transportation, lunch or break snack and the proper clothing) you may be looking at 1500 to 1800 USD a year!
... J-D.