[Question] [NeedAdvice]How to stay Focused on a long-term goal?

I have never worked for anything in my life. I’m a nihilistic person and I don’t see the point or meaning in everything. Ultimately it won’t matter. You will die and some long in to the future, the universe will die. There will be no life.

However …

I met this girl. She has given meaning to my life and all life on Earth. If she would disappear, everything will become meaningless. And I want my life to have meaning. It’s nice. So I have decided to become something of myself, to deserve the company of a such a wonderful person.

I want to improve myself. Since this is new, that I have the wish to change my self in a positive direction. So I don’t have any experience. I was wondering where should I begin. I have a goal of improving myself in these areas: intellectual, mentally and physically.

My question is, where do I begin and what is the best way to completely focus on this goal of improving myself. Should I create a schedule? How do I improve my self intellectually? Read more books, be in the company of smarter people than yourself? I literally haven’t good a single idea on how to reach this immense goal of creating a new version of myself, that is stronger intellectually, mentally and physically. I know what I have to do, but how do I stay disciplined for a journey that will take years, maybe decades(you probably think I’m insane for spending my time for one person. But I think she’s worth all the time in the world) to achieve, where you will not have any positive feedback for a long time, no support from anyone and lastly the option that I might fail.