Yup, this can be normal. Autos are timebombs ;) You never know exactly when they will "go off".. sometimes they have a short fuse.. sometimes they preflower like this, then continue to veg, while being mature.. Usually this is a sign of an early flowering pheno (short fuse auto).
I'm noticing her growth is a little stretched. Getting your light slightly closer in the starting weeks of life will get you more growth potential by week3 :)
Happy growing!