Should I tell the girl in any scenario e.g. as a joke or serious that i ate pussy before? I want to see her reaction

yes you should, eating pussy is good but you have to know what kinda girl your talking to and how shes going to receive it plus you gotta build up some sexual tension so it doesnt come out out of nowhere cause thatd be weird

Try it and see what happens. I find things work out quite well without ever having to explicitly mention sex.

Like last night I literally picked a girl up on the five minute walk from the bus station to my house.. and we had a whole night full of delicious sex.

All I did was talk to her, build up some comfort, invite her home, put on a movie say "I wanna lick you. Can I lick you (while I spread her legs and pull her panties down) then really work her pussy until she starts moaning and twisting all over the couch - then take her to bed and fuck her. Works beautifully.