Difference between a 1420 and a 1450 for usc, bc, georgetown

Hi! I am a rising senior and currently have a 1420 superscore on the sat. My goal has always been a 1450 and I will take the August and October SAT's but idk how possible that goal is. So I was wondering is the difference in score a significant factor in the admissions process? Is that extra 30 points really the make or break of my appplication? I really want to go to a school with a strong IR or Poli Sci program like USC, Georgetown, or BC but idk how strong my score is. Everything else in my app is right where it needs to be aside from my SAT score. Thanks!