Why am I not wet?!

So my boyfriend and I have been taking things slow, just grinding and I’ll occasionally give him head. He wants to go down on me, but last time I was fingered by someone it was my first and only time and it didn’t feel great, I wasn’t wet enough and i felt like I was too tight. I really want to let my boyfriend go down on me and finger me etc. but I never seem to be wet no matter how turned on I am. any ideas why??