Pornography is a very bad way to set your expectations. Real intimacy has nothing to do with what you see in porn.
Good news is you body actually knows everything you need to know. Just let it take the lead.
The first times are normal to be sub par. Just communicate with your partner. They'll probably find your lack of experience cute; let them take the lead. Thousands of years of evolution have taught you how to haev secks. Don't fight it. Be vulnerable.