Girls please help: If a guy shows his love for the girl too early in a relationship, is it completely over?

okay, here's the deal: I found the girl of my dreams, but I lost her! Now, I know exactly why this happened. I rushed into it! I took her out on a date once, but it didn't go so well. So, out of desperation, in order to get her back, I got her some flowers the next day, with a letter saying that I like her! But guess what? This ruined everything. She totally freaked out, and sent me a letter saying that I'm a sweet guy, but its best if we just stay "friends". Now I'm very upset, and I hate myself for not having any "game" at all! So, my question is, girls, how can I fix this? Is it even fixable? Or is it such a huge turnoff that nothing can make her change her mind?