I never bought into the "30 is the new 20" from the first time I heard it. I think I've always been an old person deep inside and as my age caught up, the better I became at living and being me. By 27 I could stay in on a Friday night without having to explain even though at 22 I felt compelled to go out with the rest of the crowd every now and then so I didn't seem like a party pooper. At this point in my life I look back at "old people" things I did and am grateful because they've made this stage of my life better but there's so much more I wish I had known.
I took stock of sleep very late in my life. I was always moving and working and staying up too late into the night. I had deadlines to check and "would sleep when I was dead." I think the transition between university and the first fives years as a working woman were spent in a tired haze. I'm not saying don't work hard, by all means do; just give yourself at least seven hours off each day and you can work the other 17 if you so desire.
In all my "moving" I made time for gym and other exercises when I got the time but nobody ever spoke to me about core and back exercises. I only started pilates less than 10 years ago and they have been one of the best things I've ever dome for myself. They are great for posture, balance and grounding one.
Speak to your doctor about supplements to help you with iron and calcium production. Always take an omega 3 supplement to keep your brain agile. Eating right is an important step but the truth is that we can't get all the nutrition we need from food alone.
Last but not least: laugh when you can, laugh at yourself, do good for others, go on long walks, do something impulsive every now and then and just do your best.