Princess Margriet is wearing the laurel wreath tiara that was reportedly given to Princess Beatrix for her 18th birthday. But I can't identify the bandeau of Princess Christina, probably a necklace?
Princess Margriet was born in January 1943, so she would have been 19 in 1962. So she was probably in her 2nd year of tiara-wearing. But most pics I have of her are without date, so I don't know for sure.