I recommend you really really think about it hard. Because you know, hair takes an eternity and a half to grow (not to mention it gets awkward several times mid-way), and I read pixie cuts were the most risky of all, and not just for trans people.
But if you're sure, hey, why not? If you can pull it off, that just means you're even cuter than I thought! And if you have unbearable heat where you are, it'll probably be comfortable, yeah. :3