From early on

 If you can't find happiness on your own self, inside you, then you're screwed, because everyone is on their own truly, everything else will bring you down, make you sad, disappoint and hurt you. People are never really there for the other, they don't prioritise making someone else happy or feeling good unless they get also something out of that, and it's only temporary. 

So you must strive to be happy within yourself as a default mode, something tranquil and basic, in the sense that it is your foundation. And you should manage to do it from early on. 

Fond out that you are the one who came to this life and you'll have to live first and foremost with yourself each second of the day. There's nothing you need to be happy. Only if you want to experience joy above the usual you will have to probably resort to your outer factors. But to be whole and okay with yourself you just have to know deeply that you're it to yourself and it's okay, because truly only you can know what lays within.