Very uneducated and unkind comments on here. I'm amazed just how well versed younger women are in older women's levels of vitality and energy 
I don't judge older mothers, as often they have been through a lot to have their dcs and seem to have not only the energy but the time for their dcs.
The ones I judge most are the young women who may be medically best placed to have dcs but are emotionally, and career wise well off track. The career of both parents matters so much that the poor child is shoved in nursery from 7am-7pm every day, and then shunted off to some private school because 'they have wrap around care from 8am to 6pm.' Why not go one further and make it boarding school? Then you only have to see them in the holidays, and the au pair can cover that
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Extreme huh? No more extreme than slating every older mum as 'selfish' because she might have grey hair, or a dodgy knee and let the side down at the school gate.
The oldest mum I know was 50 when she had her 3rd. No idea if the baby was planned, but I suspect not. Amazing mum. Looks 15 years younger, loves her dc, and has time to be a parent. If I was a kid I know I'd rather she was my mum, than my high powered 30 something career driven friend who is either at work or down the gym.