I would like to know how competitive entry into Physics Grad Schools is exactly; I would really like to shoot for a high-end grad-school but this semester has made me worried about things. I took Math 25 and Physics 16 this year (Harvard freshman), and found both classes really difficult; I was adjusting to the competition (kids in my class did IPO, IMO, ect), the "living" on my own, and the huge difference in the difficulty between these courses and Physics/Math I'd done in the past(Crappy public High school in TN + independent readings) and I'm not sure what my GPA will look like this semester... I definitely don't think I'll get A's in either of them, and I've heard it's basically impossible to get into any really good Grad School's without a 4.0... Is this true? Should I be worrying about this or am I just being ridiculous? I really had no idea what I was doing when I applied to College; and I don't want to make the same mistake this time... so what is it going to take to have an earnest shot at top grad-schools?