Sleeping thru the night

My mum told me earlier this week that my little nephew, Bryan is already sleeping thru the nite (and he's more than 3.5mths younger than Shawn). My brother told me Bryan will sleep from 12mn to 7am. Me so envious leh. Why am I so 'pai mia'? Cherylin only started to sleep thru the night when she was 10+ mths. Hence, I'm sort of prepared that Shawn will not start early either. Nevetheless, whenever I hear from mummies/daddies that their bbs has already sleep thru the nite, so how i can help but feel envious. My panda eyes are getting worse, and so are my mum's :P