Boyfriends ex possibly pregnant

Caley

Hey guys so my boyfriends ex just told him about a week ago her period is late and she's saying she's pregnant. Now I'm not one to say if someone is lying(but with her past she's a compulsive liar and will do anything to ruin him and I) I'm just stressed because If she is she should be roughly 2 months along and the last tome they had sex was on his birthday. (Which is towards the end of July) I told him until she pees on a stick she's not being honest but there that what if floating in my head. Should I be worried about it? I'm trying hard not to worry but their both 17 and I just turned 18. She won't get tested to see if it's positive so is it even worth worrying about?

What are your thoughts about this??