First time

Hey guys, I'm new at this but I just wanted to ask a question. 
The other night, I invited my male best friend over and things got serious, I don't think I was ready for anything to happen (stuffed happened when I was a little girl and I've never felt ready) but he started doing oral and when he tried to put it in I was too tight (I was so embarrassed and scared). 
Does anyone have any suggestions on how I can be more comfortable or not so tight? 
Thank-you