Aging is to do with our cell division rate to fix damages to our body.
What happen is, every person their cell can only divide a set number of times, when ur cells can no longer divide, u die. Human on average can divide cell around 80 times, while Asians can usually divide more times then Europeans, which contribute to Asian adults of the same age, usually look younger the European adult of the same age.
When our body is able to divide cell at a speed faster then damages, then we will be biological youthful, when it is dividing at a speed slower then damage, we will start showing the sign of aging. But the problem, is when we use a higher percentage of cell division, our cell division would also slow down, thus if we use 20% of cell division, our cell division speed also slow down by 20%, when we use 50%, our cell division speed also slow down by 50%. As a result, when we get older, we also biologically age, turning back ur biological clock, is, about taking care of ur body, so u stop causing damages to ur body, so ur body can repair damage at a rate, faster then u damage. That is also how women, aging wrinkle cream beauty product work, these products, help to maintain ur cells, to prevent damage, while ur cells repair damages to ur face, after a while, all ur wrinkle disappear (In other word, these beauty product are also health product)
There are 2 ways, to slow down ur aging speed, (1) take care of ur body, stay fit and healthy, so there are less reason for ur body to be damage, which would later lead to the need of cell division to fix it (2) some people just simply have a higher cell division rate then others, This is genetic, there is nothing we can do about it, for example, Asians people usually have higher cell division rate then European, that is why, by 30s, Asian people, usually look younger then their European counterparts. (although u could probably consider marrying an Asian, so, ur kids can have those same good genes, providing u are not worry ur husband start having an affair, by the time, u look old and he still look like a teenager. Unless u are a guy, then u don't need to worry about that LOL)