Today's exercise: climb or drive to the highest point in your vicinity and look down. If the area where you live in is flat, go up in a plane or helicopter. Look at the hundreds of thousands of structures below and around you and think about all of the people who live or work in those buildings. That is your competition.
https://cdn.europosters.eu/image/1300/wall-murals/london-aerial-view-i25259.jpg
Now think about any girl whom you're interested in. Do you have anything you can offer her that none of those other 100,000+ guys can? Even if the only thing that girls care about is running ability, are you absolutely certain that you can outrun every single one of them?
If your answer is "no", you're out of luck. The girl you're interested in will go for that guy who's richer, stronger, or better looking than you. And it's only a matter of time before she finds that person.