Ce guitarre est vraiment joli, non? Je trouve que c'est un vraiment beau guitarre! J'aime le bleu! C'est tellement beau!
Currently I'm taking a course in French.

What I wanted to say was 'This guitar is really nice, don't you think? I think it's a really beautiful guitar! I love the blue! It's so beautiful!'. I don't know if my grammar is good, though.
Myst