FROZEN BREAST MILK

Ok I have a question. So I know that our amazing milk is designed for our babies and that it changes as baby gets older etc. i exclusively BF and also pump once a day and freeze it (my LO is 7 weeks). My question is....by the time we use this frozen milk (say for example ...when returning to work in a couple months) wouldn't my LOs needs have changed?? Will the milk still be 'mature' enough for what his growing body is requesting? What are your thoughts?