I dont know what do to about this horse? follow my dream or give up?

i'm fifteen years old, and basically there's this 3 year old horse that i NEED in my life.. seriously. she was about 1 years old at my yard when i was loaning a pony and she was really badly behaved, she actually used to be dangerous to be with so i started to go in her stable and work with her and after many days of going home with scrapes and bruises, i got a strong bond with her and her behaviour gradually built up from there. i would go in every day and groom her, no headcollar, she used to make me laugh so much, and as my loan pony was in the riding school, i spent more time with the filly than i did with my loan pony. the thing is, after over a year of working with this filly, i had to leave the yard and have heard that she's got SO naughty again, and they're trying to break her in now. i miss her so so so much, there's not a day that goes by that i dont think about her, there's not a night when i dont dream about her, i sit here and cry sometimes at the thought of her leaving and not coming back.. writing this is making me cry and i'm pretty tough skinned. my dad says he doesnt want me to buy her because of the risk involved, because she's so young, but if she got sold i honestly dont know what i would do. i'm making a video to show to him to try to make him understand how much i love this filly. if i could let go, i would, but i'm just too attatched to forget about her. her and my shetlands are EVERYTHING to me. plus, she's up for sale. i could possibly get half the money to buy her but she would be sold by the time i got the other half. so i want to hear from you lot.. should i completely give up on her and let her get sold and just suffer the heartbreak, or should i follow my dream and keep on trying to get her? it would be a 5* home, turnout and stables, all the love and care she wants, and i would work her and make her well behaved again.. i'm not scared of what could happen to me if i bought her, or the injuries i could suffer, i'm worried about what could happen to her if i dont buy her, and where she would end up. i would rather suffer from broken bones than a broken heart, and life is either a daring adventure or nothing. thankyou :)