What do Braxton hicks contractions feel like and when is the earliest they can start?

Hey, so I'm a ftm and everything is scary and new to me, I'm 16 weeks and four days as of today, I'll be 17 weeks on Friday and last night I started having these tight kind of crampy feeling they would last around 40 seconds and they were a little uncomfortable but not painful after 40 seconds or so my belly would relax and everything would feel normal again, I started producing colostrum at only 11 weeks and felt baby moving at 14 1/2 weeks so is it possible that I'm feeling Braxton hicks earlier too?