Why do I feel sad trading my car?

My parents first bought a 2012 Ford fusion and I was the one that picked the car for them. I was 15 at the time and liked the car a lot. They eventually gave me the car so I had it for 3 years. I traded it for a 2013 Ford mustang gt 5.0. I've always wanted a mustang since I was a kid and never thought I would be able to purchase it. For some reason I just feel sad for selling the fusion it had 57k miles while the mustang has 29k miles. Is it normal to feel this way? I also feel guilt because my parents took so much care of it and I did as well and I have a feeling next person who has it won't care and it hurts me. I really shouldn't care but its kind of like my baby that I feel I abandoned
Why do I feel sad trading my car?
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