Young one, listen to the wise Uncle Crafty......... Put together a thoughtful (thoughtful is important and wins many points
) picnic and go for a romantic evening at one of the beautiful fishing uuummmm, I mean picnic spots along the coast, enjoy a romantic evening and then do some fishing together.
You will be a much happier man for the remainder of your life if she learns to fish. Most ladies are more impressed with the amount of thought you put into something rather than how much you spend, the ones that aren't ain't worth having around...
If fishing is definitly out for this particular event, a picnic and walk are always good, jus tgo on a lowtide night so you can check out the structure.