So I've been with my girlfriend a couple of weeks over a year, and now she's said that she wants to go on a break, just for a couple of weeks, where we're not splitting up or single, she just 'needs some space'.
I was pretty devastated at the time, especially since she only text me in the middle of my day at college, but now we've talked about it I feel a lot better about it.

So all I want to know is how long I should leave her alone for? She said 'I might not need the 2 weeks if I have some space' but I'm really not sure what I should do.

It kind of feels like she's been pushing me away over the last couple of weeks, and we are only 16/17, so I've not been in a relationship for this long, so I'm really not sure what to do.

Maybe don't contact her for a few weeks just enjoy time with your friends that's what I do.

Give her the time she's asking for. Let her contact you when and if she's ready.