Yes, MATURITIES is a Scrabble word!

Letter values in Scrabble US: M 3, A 1, T 1, U 1, R 1, I 1, T 1, I 1, E 1, S 1.

Is it a valid word?

MATURITIES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the period of time in your life after your physical growth has stopped and you are fully developed
state of being mature; full development
the date on which an obligation must be repaid

Also: maturity date, due date.

Not playable in Scrabble US: MATURENESS.