Flowering already?

Hi there.. at the beginning of the flowering phase, the plant will go through a growth spurt, so at this time she will still need vegetative nutrients that have a higher nitrogen percentage. Only once she stops her growth and starts putting her energy into creating buds (about 2 weeks into actual boom, but this can differ per strain) you should switch over to bloom nutrients, as that's when she doesn't need much nitrogen anymore, but more P and K (that's why bloom-boosters are also often called PK-booster). happy growing!