Question for mommies and sorry if a little tmi, today at the doctors office I lost my mucus plug…

Question for mommies and sorry if a little tmi, today at the doctors office I lost my mucus plug while giving my urine sample. For the last week I've been feeling pain at the top of my lower butt and my vaginal area has felt swollen and just flat out uncomfortable (especially to touch) . Ill be 35 weeks on Wednesday. How soon after losing your mucus plug did you start labor ? Also is this normal for your first pregnancy ?