Help with first semester courses

I am coming into RPI as a junior in chemical engineering from a community college, and I want to know how many credits I should take for my first semester. My hardest semester at my cc consisted of calculus 3, organic chem, two engineering classes and physics (elec. and magnetism), for a total of 18 credits. I put my work in and got the 4.0.
I know that it is going to be a major step, so could anyone suggest as to how many credits I should start off with?

I would register for 15 or 16 credits depending on if they are 3 or 4 credit classes. You want to have enough credits so you can drop any one class and still be a full time student (min 12 credits). RPI has a generously late drop date compared to many schools, so you can get a really good feel for how you are doing before the deadline.