From Marten Stol's Women in the Ancient Near East (de Gruyter, 2016):

Martha Roth has demonstrated that a girl married between the ages of 14 and 20 and a man between 26 and 32.23 Ancient Greek and Roman sources show this was also the situation further west around the Mediterranean Sea.24 This has consequences for our view of family life. Because the men were older and died earlier than their wives, there must have been many widows. In Greece a man was thought to be old in his sixtieth year. If his son married when he was thirty, he would in a sense replace his father.25 The relatively old Greek laws from the city of Gortyna on Crete (ca. 450 BC) in their last stipulation indicate that a girl could be married off when she was 12 or older. The Jewish Mishnah, from the beginning of our era, states that a boy of 18 is suitable for marriage (ḥuppā) (Aboth V 25).26 The early Greek poet Hesiod makes the following comment in his ‘Works and Days’ (695–701):

"Take your wife into the house when you are the right age, neither very much short of thirty years nor much beyond that: that is marrying time. Let a bride be four years past puberty; let her marry in the fifth. Marry a virgin in order that you may teach her devoted ways, and marry especially one who resides near you, after looking carefully at all things around you, lest you marry a source of laughter for the neighbours.27"

A Middle Babylonian text tells how a merchant ‘took’ a girl who was a half-el tall from her parents with the intention of giving her as a bride (ana kallūti) for his youngest son.28 As her bride-price (‘her silver’) two beautiful garments worth two shekels of gold were given to each of her parents. Really the girl was worth more, but instead of the ‘rest of her silver’ the buyer promised to take care (zanānu) of her. She was therefore still a child that had to be supported for some time. An Assyrian text speaks of a girl who was ‘two half-els’ tall and who was likewise given as a bride. Another bride was ‘four half-els’ tall.29 For a boy the minimum age of 10 years old applied in cases of necessity, the legitima aestas.30 It is difficult to imagine such tiny children getting married, so these situations may have essentially been betrothals. A letter says that a girl had already been formally promised to the ‘son of a citizen’ ‘since she was small’.31 In a myth we find the unburdening of the heart of a tender young goddess in the words,

"My vessel is too small, I do not know how to … My lips are small, I do not know how to kiss (‘Enlil and Ninlil’, 30 f.).32"

A Sumerian proverb says that a wife should not be very young:

"Unlike a donkey, one does not marry a three-year-old wife (SP 2.81)."

We don't have any sources on Mary's age to Joseph, besides the Protoevangelium of James. And even then, that document says that she married a decaying widower because it was to preserve her virginity as he didn't have a sex drive, and was seen as a respectable man.

And Joseph, throwing away his axe, went out to meet them; and when they had assembled, they went away to the high priest, taking with them their rods. And he, taking the rods of all of them, entered into the temple, and prayed; and having ended his prayer, he took the rods and came out, and gave them to them: but there was no sign in them, and Joseph took his rod last; and, behold, a dove came out of the rod, and flew upon Joseph's head. And the priest said to Joseph, You have been chosen by lot to take into your keeping the virgin of the Lord. But Joseph refused, saying: I have children, and I am an old man, and she is a young girl. I am afraid lest I become a laughing-stock to the sons of Israel. And the priest said to Joseph: Fear the Lord your God, and remember what the Lord did to Dathan, and Abiram, and Korah; Numbers 16:31-33 how the earth opened, and they were swallowed up on account of their contradiction. And now fear, O Joseph, lest the same things happen in your house. And Joseph was afraid, and took her into his keeping. And Joseph said to Mary: Behold, I have received you from the temple of the Lord; and now I leave you in my house, and go away to build my buildings, and I shall come to you. The Lord will protect.