Thoughtfulness is grossly underrated, especially in dating, always err on the side of doing something. You don't have to make a grand gesture or do anything extravagant, but you should definitely acknowledge it's Valentine's day and do something, even if that something is as simple as going to the supermarket before she arrives to buy some nice breakfast ingredients so that you can wake up early and make a cute Valentine's breakfast together.
Seize any opportunity to demonstrate you have thought about someone. The gap between doing nothing and doing something is ten times greater than the gap between doing something small and doing something big. Far better to be seen as eager than to be seen as someone who doesn't care.