At the end of prologue, most girls will have lvl 10, so u clearly missed some events and content, check the hints in girls tabs.
What happens is that I haven't been able to do even part 1 of the prologue mission because I don't know what I have to do, I mean, in a few words, I haven't started the prologue mission, I'm stuck at point 1I have gone everywhere at all hours but I don't know exactly what to do, I have the girl on the beach at 5, I have the housewife at 5, but what is Rebeca, and the other two girls I haven't I have because they ask me to raise Rebeca but she doesn't level up
So, to be sure, Rebecca is the blonde girl in church. At first u just have to talk with her to get lvl 1, then spend time and talk for lvl 2. Again spend time, and the task will be to recruit more girls for guild, that wud be Shino (in the bar) and Lucy (cat girl, in dojo at night). Then next quest shows up; "Find Jimmy", u will get another girl with that. After that, task is to "visit Rebecca at church" - this gives lvl 3. Spend some time with her, and (the task) "visit her in the evening", this will give lvl 4.
I hope it will help u.
Those are the girls I have so far, but I haven't been able to move on. Shino is at 1 because you couldn't advance and Lucy is equal to 1 and Rebeca is still at level 2 and the other two are up as far as I could but I don't know what else to do, I need a girl according to what I read in your comment but I have already gone to all places at all times and talked to everyone at all possible times and there is nothing, no event happens, nothing happens 
