The word is not angel but spirit. Here original text. It said “ruh” and ruh is translated as spirit.
Code:
وَمَرْيَمَ ابْنَتَ عِمْرٰنَ الَّت۪ٓي اَحْصَنَتْ فَرْجَهَا فَنَفَخْنَا ف۪يهِ مِنْ** رُوحِنَا** وَصَدَّقَتْ بِكَلِمَاتِ رَبِّهَا وَكُتُبِه۪ وَكَانَتْ مِنَ الْقَانِت۪ينَ
12-** And Mary, daughter of 'Imran,** whose body was chaste, therefor We breathed therein something of Our Spirit. And she put faith in the words of her Lord and His scriptures, and was of the obedient. At-tahrim(66)
I explained why Qur’an use “we” instead of “I” in post #457.
For actions through which God use means and intermediaries or to point witness of those it is said “we” but for personality of God it is said “I”. And do not forget one-third of Qur’an is about Tawhid which means God is one and unique by attributes, actions, substance or relations etc.