BPS accredited Psychology degree (choose modules in Forensic Psychology when applicable), then go for a BPS accredited Forensic Psychology Masters and onwards.
The straight Psychology course as your undergraduate degree instead of a Forensic Psychology undergraduate course in case you find it's not the right area for you.
During your undergraduate degree, you would be well advised to apply to the prison-run Psychology work experience schemes.
I suppose you're American with your '12th grade' and 'which college', if you're studying in the UK go by the best known and rated university departments that you can achieve with your grades.
A final point, Forensic Psychology doesn't involve learning how to be the guy you see in Lie To Me. You won't learn how to tell if people are lying.