Advice for joining the crew/rowing team?

Question

I want to join the freshman rowing team when I start college in September. I've been using the rowing machine at the gym off and on all summer.

So far my best 2K is 9:08 and my best 6K is 29:17 (I know I'm slow...)

Does anyone have any critiques/tips on how to improve during these last few weeks before school starts? I'm a girl, 5'2" and about 128 lbs. Thanks!