Why am I stronger than guys who bench 250 when the most I've ever bench was 165?

I am in High School and I don't have weight class nor am I on the football team but I'm stronger than a lot of guys who are who bench 250. I have weights at home and I lift them every day but I cannot afford to buy more weights so I've been lifting 165 since middle school. I can get 165 like 20 times, sometimes a little more. I want to increase my strength so i may take the class next semester.