Help explain one life to live story line!!?

Just started back watching the story and very confused starr manning is dating cole thornhart who is supposed to be older than her. But I remeber back when Starr was born Marty Coles mom helped to deliver her and then Todd kiddnapped her cause Blair was sleeping with patrick thornhart and got pregnant with Brendan who died after a car wreck correct then patrick and Marty then get together and so forth get married then leave town everybody thinks Patrick is long dead. So Marty returns 15 yrs later with son Cole and He and Starr are dating but he's older how Starr was born already when he's parents got together plus don't he and starr share a brother also?????