After I graduate high school do I admission to a graduate school or an undergraduate school knowing that I have 3.70-4.00 GPA?

Answer 1

After you graduate from high school, you apply as an undergraduate, whether you finish with a 4.00 or a 1.00. After you get your undergrad, which on average takes four yours, you can then apply to graduate school if you do choose. They are two completely different things.