Here is a very general list of what most people would include as indication that they are near to optimal health. Remember that this list is simply opinion. As you go through the site you will see well referenced articles that offer signposts to what might be the best way to achieve your health goals.
Deep and restorative sleep
Good gut health / digestion
Thick lustrous hair
Optimised hormonal balance
Lean muscle mass
Adequate bone density
If you can not tick all, or even one of those things on that list don't give up!
Reaching optimal health appears to be achievable and there are many strategies you can adopt to improve your life at any age.