Probably when I was a primary school child in terms of feeling good - I was a healthy weight, very strong and that was before I started comfort eating and learned to hate my own body. But that's probably not what you meant!
I now see I looked pretty good in my early/mid twenties but didn't know what to do with myself (on account of all that self-hatred). Shame I didn't realise how decent I looked at the time and enjoy it more.
I am now so very pregnant with second child at 36 and I look and feel bloody awful.
I've already booked my friend who is a PT to sort me out once baby is 3/6 months old. I have looked like shit for most of my 30s so far, never worse than the past 3 years, and as this is my last baby at least I will know post birth that this is the body I'm left with and can work on getting it stronger and less repulsive from the ground up.
The main thing that would make me feel better these days would be to be stronger and fitter. I will always have stretch marks, section overhang and saggy boobs at this point, but I would like to be able to run after my kids/climb two flights of stairs without puffing, and to have energetic sex with my partner again instead of choosing only positions that won't expose my flappy bits and lack of stamina!
In terms of looking better, I think if I could be bothered to do make-up and wear sexier clothes that would be a step in the right direction - but I am aware I never have and never will be a raving beauty, age will inevitably make me look 'worse' by most metrics, and I think focussing on trying to 'look good' is going to be a negative path for me - so I instead embrace my ever-growing natural impulse not to give a fuck, I feel this is far more sustainable in the long term!