Wow, thanks, that's quite a compliment. ^_^ I made the image myself, and my girlfriend coded it for me, because she's a love.

Thanks for the comment, I really appreciate it :)

Being the grammar freak I am, I can answer your question:

"May my wavering heart be tall and proud" is a sentence, but it would sound better as "Be tall and proud, my wavering heart."

Or, you could go with this:

"My wavering heart, be tall and proud" <- Addressing your wavering heart, telling it to be tall and proud