When you don't care about Earnings, Studies, Career, Friends , family, Money , things or any other relations for that one Person is different kind of Love you have for that Person
Maturity ? Same Person can have different level of Maturity in different Aspects of Life. It has nothing to do with Age. Person who is matured in business can be Immature in Relationship or Vice Versa. More the level of Pain & Experience, more Mature you become.