Well I have sorted according to age as to me young lady can mean anything between 0-25 years so lets go shopping...

0-3 years

clothes making sure that you know the size, cute hats, childrens books, toys

4-8 years

cute little shoes, toys, board games, hair clips and other hair accessories

9- 13 years

Movie tickets, books( if they are into a particular author), magazine subscription, stationary, horse back riding lesson (1), cheap costume jewelry

14-17 years

A gift voucher for I tunes, mobile phone credit, book voucher (if they like reading), money, mobile phone pouch, small purse, offer of free driving lessons (by you)

18-25 years

pedicure/manicure voucher, massage voucher, resturaunt voucher, bottle of champagne, book voucher, pashmina, plant if they have their own place and like gardening.