can i still go to college if im 19?

Just really need some help. had to drop out of college when i was 17, and i want to go back for biology. i cant find any solid step by step plans online on how to do that, and i just really need some help. i want to go into entomology or even biochemistry, but i just dont know how. i really just need some advice please. thank you 🙏🙏