If you take the blame,then you'll probably have to pay for any damage as your cehicle was probably not insured for six,you could get sued if anyone decides they've suffered injury,Police and insurance companies don't look kindly to being lied to,you'll at least get points on your licence,if not a ban. Don't know what you can do about threats,apart from confide in your parents or someone in authority. Apart from leaving and knowingly allow someone without a full licence to drive (unless she/he was displaying L plates) then you did nothing wrong. Don't get in trouble for others