Congrats on your acceptance. At some point you need to think about what you want to study in college. If you want to be a math major that is one path, if you want to be an engineer then you should focus on schools that offer engineering programs.
I am not a fan of the 3+2 programs for many reasons including the fact that it is an extra year of college to fund and many people do not follow through and complete the 3 + 2 programs for different reasons (ex, don’t meet qualification requirements, don’t want to leave their original school).