Honesty tends to work.If this was a true mistake,just explain to your employer what happened

They told you what to do. "Go over your timesheet very carefully and take your time". I would suggest you do that from here on out or you will not be working with them much longer.

There are loads of potential hurdles for teenagers in work, many of them legislative, moms and dads have to be vigilant about that. There is loads of guidance from the resource in the box below on this topic, they also have guidance for all peeps who are searching for work, or who have to change careers.

You should send them a corrected bill. You should apologize and admit that it was unprofessional, without making excuses. And you should tell them that you completely understand if they would prefer to find a new subcontractor. That is the best route, and has the best chance if any of you getting any work from them going forward ... and avoiding a law suit.

As your boss said, go over it carefully and re-submit it with any supporting documents you may have to each job- a receipt or work order or something with the clients signature on it. Also, perhaps a letter explaining the situation, letting them know you were not at all trying to deceive them and that in future you will make time to correctly fill in your time sheet.

At least you told your boss the truth that you may have made mistakes without realising. If this is the first offence they should realise it was just a silly mistake and and that you have learnt your lesson.

It has obviously happened before within the company and there are dodgy people out there always trying to make a buck. You seem trustworthy so I'm sure everything will work out in the end. Just try to rectify the problem as soon as possible- your employer will have more respect and trust for you if you do.

Good luck!