first paragraph has some tense changes that go from present to past
It was the winter of my sophomore year when I had to face my fears.
You say fear in the first paragraph, so maybe connect this sentence with the next and take out fear
I was excited, yet shaken by the thought of having the team rely on me.
interesting, but it somewhat goes against your intro. maybe you can shorten your intro to something about how at first it wasn't that you didn't see the importance of teamwork, but that you were afraid? then in the body, it will be the discussion about swim. therefore, you don't have to list tennis, or w.e
The day dragged on
sounds negative somewhat
I gazed at my teammates, dreading what would happen should I be the cause of us not making it to the finals.
this was an example of that fear, you can talk more about it- how this was what make you wary of teams, because of the pressure...or soething along these lines
The whistle was blown.
I like this paragraph, though it is long, but the imagery is quite nice.
For the rest of the meet I pondered over the aspect of being on a team. A team player is more than just sticking together through successes, but also sticking together through disappointments.
second sentence pops out of nowhere, even though you are talking ab out your team, need a transition word or phrase like I realized that OR They made me see that.
My experience at this swim meet has allowed me to burst my bubble.
is that a good thing?
Previous to this, I had thought that it did not matter whether I was a team player or not, but now I realize how wrong I was.
now or then?
I have learned that participation is important to a functioning group.
you should embed this more into your participation and not just say it
in the Last sentence, with misconception, what did you mean? your attitude?
Comments: Nice overall, some things to cut down maybe are the intro, about other things not related to team/swim/learning/change/etc that don't really make your point about how this was a significant experience.
I hope you don't get erased for bad title. Good Luck~