DD3 is 12 months and has hip dysplasia. She wasn't standing either so I had a session with a paediatric physio and it was fabulous. She just gave me lots of tips to encourage her to stand on her own. I was told by her orthopod not to worry but I just felt it wasn't right.
Definitely see someone if you feel it's not right. I'd start with a paediatric physio but that's probably because I had such amazing success so quickly. Good luck.