Talking to herself

Hi, my daughter who is nearly 13 and only got diagnosed with ASD in November last year, has recently started talking to herself all the time, she has always talked to herself on occasions, like when she is playing a game or something,  but at the moment, it's all day everyday, into the early hours of the morning.  She laughs, chats, and talks like she is having a conversation with someone. I ask her who she is talking to and she says herself.  She struggles socially and at the moment has no friends. Which is heartbreaking for me, but she says she doesn't care and it's way less drama. I know children and adults with ASD, do talk to themselves to help them process thing, I mean I talk to myself sometimes, think we all do, but not to the extent that my daughter does. Is this a common thing, or should I be worried please? 

Thank you for taking the time to read, sorry its a bit long.

Jackie