I would do your project for school with an experiment or two and that might help you see if you have social anxiety or not. If you have social anxiety, some of the face recognition problem could be because you are not looking at the other person long enough for their face to "register."

I would go to a store with multiple clerks (grocery store) and buy something and gaze at the clerk as you are checking out, not just when people in front of you are checking out but when you get to her; say "hi" and tell her "plastic's fine" :-) mention something about the weather, that sort of thing while actually looking at her. Make sure you look at her for at least 10-20 seconds and are thinking about her looks; length and color of hair, even color of eyes, whether she wears glasses, has any marks or other distinguishing features on her face, how tall she is, etc. Then, I'd go back in a week and "look for" her/her line at the store (buy something else).

If you have trouble looking at her at all, you could have social anxiety. If you have trouble just greeting her and talking about the weather while looking/smiling at her, you could have social anxiety. If the idea of doing social experiments gives you the willies :-) you could have social anxiety.

Lots of people have trouble looking other people in the eyes. You can imagine how that would make it difficult to remember them if you don't properly look at them in the first place? You can practice that and that will help you recognize the people later.

I often think up ways to help myself with that and with just having little chats with people, especially store clerks. I make a decision to smile at someone while looking them in the eye and greet them. That's very hard sometimes! But the more you do it the easier it becomes. Sometimes I go for a walk in a busy area and decide to look at everyone that passes and greet them with a "hi" (or "hey"), female AND male. Meeting the eyes of strangers is very hard. Sometimes I sit on a park bench or ride a bus/subway and pretend I'm a spy or have witnessed an accident/crime and have to describe a person to the police. That too could be some of your problem; I didn't have the "words" to describe things. Just sitting on a bench in a mall and describing people, making up stories about their life can be loads of fun. Associate obvious features/clothing with jobs, etc. raincoats=detective or spy, workboots=construction worker, etc. Work up to faces, big nose, "that guy looks like Jimmy Durante/Bob Hope/Jay Leno, that sort of thing. Being able to use words and associate like that so when you meet someone new it "sticks" is essential. You not only have to look long and and hard enough to see but you have to be able to describe what you see to yourself so you see the person's "uniqueness" and can identify it later.