I think it looks cute! I see what you mean about the F. I didn't notice it before I read what you wrote, but on reflection I think lower case would work better - it matches the lower case used for 'for the wedding of'.
Keep the capital F in formal invitation to follow. Take out Th in the date. Maybe write out the state name.
Personally I would add your last names so people know who the wedding is for. While it may be a given to your closest people, those who don’t talk to you everyday may not be aware of your engagement and put 2 and 2 together.
I agree with adding your last names and removing the "th" in the date. I do think I like the lowercase F though for the reason Rosie stated. It's the only capital letter used in that font and it sticks out.