Curious

So this is my first pregnancy I am 31 weeks. I might be stupid but can you tell when your dilating or effaced at all? I have measured 2 weeks ahead my whole pregnancy. I’m not experiencing any contractions but I was “trying” to shave down there and my vagina feels swollen and almost as if it’s opening I guess. Like my lips just stay apart, and I Just don’t know how to bring this up to my doctor either🤦🏽‍♀️