Some advice please (guitar related)?

That does suck, sorry to hear that your mom came down on you like that. Maybe you could put together a powerpoint presentation, detailing your pion for playing the guitar and that this guitar you want/need will only fuel it further. You might also point out that you will have own this guitar far longer than she would any car she ever had or had and the guitars value never goes down. Something to that effect... Good luck. If it doesn't work, take your squire to a guitar tech and have some killer new pickups and strings put on.