Church teaches we can reach perfection in any state in life. How can Paul say celibacy/virginity is higher than marriage?

One gives greater means than the other, but the key is this:to follow what one sees is God's will for him/her is not lacking in generosity, and so perfection is possible. Marriage, from differences of male & female psychology, requires much giving in, the opposite of selfishness, and so can be a means of spiritual growth.