We don't really know. Certainly Mary came from a good family and +Joseph's pedigree is a good one too. Likewise, he was a skilled craftsman. What "rich" actually means here, who knows? Certainly they were not of the ruling class in any case.
"The other thing that caught my eye was that it said that Mary was given grace at three years old. Is this the same grace that the angel mentions later?"
This passage?
"And the child was three years old, and Joachim said: Invite the daughters of the Hebrews that are undefiled, and let them take each a lamp, and let them stand with the lamps burning, that the child may not turn back, and her heart be captivated from the temple of the Lord. And they did so until they went up into the temple of the Lord. And the priest received her, and kissed her, and blessed her, saying: The Lord has magnified thy name in all generations. In thee, on the last of the days, the Lord will manifest His redemption to the sons of Israel. And he set her down upon the third step of the altar, and the Lord God sent grace upon her; and she danced with her feet, and all the house of Israel loved her."
I honestly don't know, but I don't think so. I think it may refer to a special grace she received to stay in the temple for nine years, but I'll find the time to see if the Fathers have anything to say on this. The line I have always cherished because it is so graphic is: "And he set her down upon the third step of the altar, and the Lord God sent grace upon her; and she danced with her feet, and all the house of Israel loved her." The image of little "Panagitsa" dancing before Almighty God is so wonderful!
In Orthodoxy we celebrate her entrance into the temple with a very lengthy devotion at night during which we chant:
"After thy nativity, O Lady, Bride of God, thou didst come into the temple of the Lord, as one consecrated, to be reared in the Holy of Holies. Then, also, was Gabriel sent unto thee, O all-undefiled One, bearing nourishment unto thee. All the powers of Heaven were amazed when they beheld the Holy Spirit take up its abode in thee. Wherefore, O most pure and undefiled Mother of God, who art glorified in heaven and on earth, save thou our race."
Here is an icon for the feast:
