1 1/2 to 2 hours worth of practice 4 hours before a lesson, or 30 mins right before??

My lessons are private with a coach during an open freeskate session and she suggested I get in practice before hand. The thing is, 30 mins during freeskate right before my lesson costs as much as a 2 hour long public skate session 4 hours before. Also, I may be a tad bit intimidated and embaressed as a beginner figure skater to be skating on open freeskate ice with tons of girls. Public skate is also really empty, and I have a lot more time. So my question is, does it matter if I do either or? Or should I stick with the 30 min practice before hand?