Recommendations for Penn as a transfer student?

I'm thinking of trying to transfer to Penn, but I'm not sure who to get recommendations from. I have two from HS from my principal and science teacher, but should i use different ones since I'm in college now? I just started and i figured asking a recommendation of a professor now isn't too good of an idea considering I've only known them a month or so, but the HS are a year old. I'm a freshman at Lehigh University in the engineering program and i want to apply to the Penn Engineering program