Hi girls

Chloe - just wondered at what age Muslims start observing Ramadan? Is it a personal choice and is there an average age most start at? I would imagine small children and babies don't fast all day, am I right? What about for pg women and those who are elderly or sick? Do they adopt a less restrictive fasting regime?

Sorry about all the qns, just curious! And is it okay for non-Muslims to wish Muslims 'Ramadan Mubarak'?