Under the 5th centile???

I had my drs appointment today to go over my 32 week growth scan. I’m now 35+3 and she said she saw that baby is measuring small, not drastically small but slightly under the “normal”, he’s at 1.9kg. then goes to tell me that his femur bone is slightly smaller aswel. She said something about him being 3rd centile?? She told me that it could be dwarfism or that the sonographer couldn’t measure him correctly that day. She then tells me not to worry and it could be nothing .. why tell me it’s something and then tell me nothing? Not that I have an issue with this at all, but has anyone been under the 5 centile but everything was ok and he/she came out full sized? Sorry I don’t know the correct terms so please forgive me if I sound rude