4.0 as a senior?

I think you may want to ask someone at your high school this question. I understand that some high schools have the ability to award grades that qualify for more than the regular 4 point system. If yours does this, you may be able to make enough points as a senior to balance the poor grades you had as a freshman. It’s impossible for someone outside your school system to know the exact answer. I suggest you ask a trusted teacher or administrator.

What Jack wrote. But, if 4.0 means a perfect grade point average, then at a school with that kind of grading scale, it would not be possible to get a perfect average with any grades below that, at any point that was included in the average.

Sometimes people talk about their GPA meaning their current GPA for the current term or current year, though, in which case earlier grades have no effect on that GPA.

Your freshman grades will have a substantial impact on your eventual gpa. You can’t get around that. Perhaps you should consider going to a junior college for a year or two then transfer to your chosen university.

Some schools exclude Freshman grades; others do not. Some colleges focus on your Junior year grades because your senior year grades are too late for inclusion before colleges accept new students.

As @Hawaii_Jake said, talk to a school guidance counselor, in fact call them tomorrow before they are gone for the summer.

Not possible. An average is made up of adding a lot of numbers and doing division. You freshman numbers are already low. Mathematically, you can’t reach 4.0. You should know that from math class.