You'll need to eavesdrop on Ellie and Julia about the whole lesbian stuff, then you can proceed with the trampoline, the video game and the "bikini deal" until the soccer match on day 15.
At the soccer match choose this:
View attachment 621683
She will tell Dylan she has to leave and before leaving there's the kissing option, afterward you get this:
IF you're not using unren to add points to the game, then you'll need that point for the bathroom scene later on (assuming you're on Dylan's path) After eavesdropping on Ellie, Julia and the other lesbian girl you can choose to go back to pick Dylan after the match.