I could understand all of this if I'd ever made anything before. I tried out for basketball, volleyball, and softball and my answer is "there's always next year!" Eventually, there won't be a next year.
Have you played the sports before? When you didn't make it did you keep trying or move on to something else?
I'll give you an example. My primary school our softball team was red hot. Every year. To the point that the softball coach would 'scout' the t-ball teams so he could hand pick who he had in his teams the next year (five girls my team went onto represent state) (when I was in Year 6 we won the regional knock out championship for the eighth time in a row) I don't know why but all the girls who played softball in the region went to this primary school. We had a brilliant coach. In Year 5 one of the girls had just started playing and didn't make the team. I was still made to play t-ball this year (I was a year young and the rule was if you were you had to play the more modified sport. I was playing modball on the weekends so I was an unhappy girl) I remember her going to every training, she was allowed to be bat girl and she practiced on her own. She made the team next year. She'd been pitching for about six months but never got the oppurtunity to pitch as she wasn't considered better than our main pitcher.
She now pitches for Australia. Has done since 16 years of age. She was SO determined and she kept going.
You could give up. Or you could keep trying. Just stick to one thing. If you keep swapping sports, you'll be coming up against girls who have played the sport for years. It's always going to be hard in that situation.