First signs of growth will include the following in no specific order (it is different for everyone)
Fat Redistribution to the Breasts
Odd Itching Sensations in the Breasts
Odd Pains or Aches in the Breasts
Odd Tingling Sensations in the Breasts
then after a time (again different with everyone) you will start to bud (Search the forum for info on that).
Happy Growing to you!