How quickly does "friend zone" set in?

I met a girl this week, hung out with her a lot. It was at this tournament that i met her. I thought we really hit it off, although now im kinda wondering if shes just a really friendly/flirtatious girl. She was hitting me/ slapping me a bunch the first night, playfully that is. And she smiled at me a lot when i looked at her or smiled at her. and during the tournament i was giving her a lot of compliments and moral support and she would always act a bit flustered. anyways, we were chatting yesterday which was gonna be the last time i saw her for a month or two, and she said something about being glad to have met a friend like me, that i seem like a good friend.. and im worried that im just stuck in the friend zone with her now. Can that seriously happen in only a few days? I still want to have a shot at asking her out someday