I need help with me and my 3yr old filly!!!!!!!!!!!!!?

Ok i have been riding since i was 8, and riden many horse of different kinds. i had this filly since she was 7mons old and i taught her every thing there is to know, and she is now 3ys old and is get broke right now. she is very sweet and easy to handle, and the trainer said she is gonna be laid back and not very spooky. i'm a begininger i could say, no one taught me how to ride right, and now going to my cousins which barrel races, and she will teach me to ride better. i have a fear about loping due to an acciedent i had trying to get a horse to lope, but i still lope a lil bit though. i don't know if i should keep my filly or sell her cause i had her since she was 7mon old and the trainer said she is a gonna be laid back and she is gentle. i'm very stressed and don't know what to do cause i don't went to get rid of her and it will break my heart if i had to get rid of her. i would love to get a 2nd opion before i do any thing.