90% effaced

Last Thursday I got checked for the first time and my doctor said I was already almost 80% effaced and 1 cm dilated, which doesn't necessarily mean much, but a little early since I was only 35 weeks. Yesterday (4 days later, 36 weeks) I went again and asked him to check me and now I'm about 90% effaced and 2.5 cm dilated. He said since this is my first he wouldn't be surprised if he saw my back before my next weekly appt in labor. Anyone else have experience or knowledge with this? I'm freaking out cause I don't want to have him early