You were offered this place because you met the requirements. The doubt is common, and it is not evidence.
Talking to a person helps more than any plan we can produce. These lines are free, confidential and answered by trained people.
Your campus also has a counselling service, and it is free to students.
Whether you will find it hard. We cannot predict that, and neither can anyone who has not taught you.
Name the one foundation subject you are most worried about, and find one resource for it before week one.
Ask about academic support in week one, not week ten. Every university has it and almost nobody asks early.