It's the exact same case with me...my doc told me to get my cervix checked and I did so...found that it's not at all dilated and can go full term with my baby...I'm too a 1st time mom and such kinda pains freaks me out a lot too...but at the end of the end,if the baby is fine then everything is fine
You can't base when baby is gonna come off of the mucus plug your body can alway create a new one
Well maybe the baby is starting to dropping but I don't think so maybe some Babys come early it could be I am a second time mom well will be but with my first he was late and this one I am due Saturday and she drop around 35weeks and she still not here sometimes when u start loosing your plug it goes little by little but what's unexpected is if they will come on time or early or late it depends on the baby so don't worry u will be fine and just relax and see what happens good luck;)