so in this situation it's hard, you must talk with your sister and tell her you feelings tell her the truth and lie tray to let her understend you that you love the girl (jen) ,,,, also talk with this girl tel her that your sister was right because it's her friend and it's really hard to accept it you 2 must tell her that you love eatch other and will do the impossible ,, and you must wait a littel bit for her give her some time . and hope you can hanel it.
:)