Replying to Tonights the big night!!!!!!!

I really don't know if I've given this too much thought or not enough thought or maybe the right amount of thought, fuck idk. But tonight after dinner I'm planning to propose to my gf. I'm freaking the fuckout right now. Anyone got any advice on how to stay cool and not totally blow it. I'm so fucking nervous like I know I got this or at least hoping I do but this is huge theres no redo. That what scares me. Sorry about all the rambling and shit I hope you night goes well too ns.