Could this be PTSD?

My daughters school phoned me today. The explained that she had a good day but they believe she may have PTSD. I've read up on it and it could be a possibility.  

She has been through so much the last few years and it has had a massive impact on everyone especially her. For example, she got taken out of our care and nearly put into care. There was a lot of trouble with emergency services, her going missing, being arrested and taken into custody many times. Many family members and pets have died. School issues which started it all off. And a massive move. That's just a few. She tried commiting suicide and self harmed for years. 

It started when she was 12, she's now 15. She's always struggled when this all happened and still does. She can't eat curtain food which reminds her of hospital, for example, toast, biscuits, apple juice. She won't go to any places that remind her of what happened. For example, the park, certain roads, part of the forest which includes a certain tree. Even a member of the public who walks past her regularly just reminds her. It could be the same lady who helped her or she looks similar. I've noticed that when a police car or ambulance goes past or she sees one, she gets twitchy and seems to become a bit distressed and distracted. Even hearing sirens is a trigger. She's had constant nightmares about it and it comes and goes during the day and feeling the same emotions and feeling as to when it happened. She constantly seems on edge. Could this be because she has developed PTSD