Riiight. Mary worship is wrong. Sorry if that offends.
It makes perfect sense for God to purify the woman who was going to carry God in her body for nine months and then have (with St. Joseph) the raising and education of Him for all of His childhood. It is contrary to nothing in scripture, and indeed tallies with the angel Gabriel's salutation - "Hail, full of grace" (in the Greek, the verb form indicates a complete and perfect fullness) - with no room left for sin.
This does not mean that the Virgin Mary is divine or worthy of worship. The Church has always distinguished between worship, which is due to God alone, and the honor paid to saints, especially the Virgin Mary.