Quote:
she said this shouldnt change our friends relationship and we should still stay like it was before.
So you two had casual sex and you want to marry her now?
Don't overthink she gave you all the info you need to know, keep it at a "friend" level and don't mention relationship unless she does. If you really want her to make her your gf:
Option 1: Date other girls, be more available for your other friends too. Have hobbies, put her on the 5th place. Decline her sex sometimes.
Thermonuclear option: Fuck other girls, make sure she finds out but not by you. If she ever brings it up, say that you two are just friends, then fuck her afterwards. Leave after sex.