All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
There is nothing wrong with you being named with the name Mateen as this name is not peculiar to the Lord [Allah]; rather, it is permissible for a person to be described with it and be named with it.
Mateen in the language means strong and solid. Lisaan Al-‘Arab reads, “The Mateen of everything is the strong. He said, a Matn man is the strong and the solid. A Mateen cord means a solid cord. Something Mateen is solid.”
Based on this description, that word is not something peculiar to the Lord, and there is nothing with you being named with this name.
For more benefit, please refer to fatwa 88517.
Allah knows best.