What should I do if I'm friendzoned even after all the efforts... I'm 21M and she's 22F

I'm male (21)

Well there was this one girl (22) I met recently...

My honest state at the time I met her was I'll stay away from girls and focus on my career and then she came into my life ...

For a month we played, talked literally a lot, got drunk, I dropped and picked her up while she was visiting her parents... We gossipped, sent a small but meaningful gift for her birthday...and before me all the people around me realized that I've fallen for her ..

Before meeting her my life was very depressing... And my life after meeting her was a complete contrast...

To figure out my feelings I kept walking for days like literally 10kms per day ... And every time I convenience myself that I'd stay away from her ( I have no reason to stay away from her) she appears before me and all the walks go in vain...

Now I'm writing all my feelings in a book (I've already written 30 pages till now I feel like I'd still write another 30)... From the time I've met her and I'm planning to propose to her with that book and a letter...

That book has all the moments I've spent with her, how I see her, who she is in my life.... All the secret efforts of mine...

But after all these efforts the only thought I've had was if she was just genuinely being good to me and sees me only as a good friend... What should I do...

I don't think I'll be able to take a no .. I'm not even able to imagine what to do if she says no...

What to do if she friendzones me even after all those efforts?

PS: Both of us have never dated or been in any relationship for our entire life.