Why would she call me an acquaintance?

I’ve known my crush for almost 4 years now, and I would characterize us as friends. We hang out just the two of us and text every day. Last year she got me a gift for my birthday for the first time, and she signed the card “your acquaintance.” I think it’s very clear we’re not just acquaintances, I mean you don’t talk to an acquaintance every day and make plans to hang out with just them, right? She also talked about wanting to see me more in the card. Is it possible that she likes me back and didn’t want to label us as friends because that would be friendzoning me?
Why would she call me an acquaintance?
Post Opinion