By joining a team sport, you have made a commitment to that team and it would be unfair to then not follow through on that commitment. Plus, it teaches children responsibility and ownership. But there is always a balance. Your 11 year old daughter is old enough to understand that sometimes you have to choose, although you may not like it. My 13 year old has been playing soccer since she was 5. She has had her share of missing activities (parties, etc.) because of practice/game conflicts.And there are times she is unhappy about it, but she loves playing soccer so in the end she's OK with it. If your daughter is really enjoying playing, then she needs to commit to it (especially since practices are only one a week). The fact the team hasn't won a game yet isn't an excuse to skip practices/games.
I know it's tough to make those choices. My daughter also played basketball at her school this past winter. She had an opportunity to go to U.S. Women's soccer game in Frisco back in February, but the game was on the same day as her basketball tournament. She was so mad because she really wanted to go to the game! But she knew she would regret it if she missed her b-ball tournament so she made the hard choice. Her b-ball teammate, who is also a big soccer player/fan, chose to go to the soccer game., which meant she'd be able to play in the first b-ball game but then would have to leave. Only guess what? When the time came, she couldn't leave! She burst into tears, she wanted to stay and play . . . and she did. And their b-ball team won the tournament! Amazing teamwork . . . and that's what you want to instill in your children.
Don't get me wrong . . . there will always be exceptions. Illness, obviously. Or a very significant moment in a family member's life (sibling's h.s. graduation, grandma's 100th b-day, etc.). Or perhaps religious reasons -- a girl used to play on my daughter's soccer team whose family objected to sports on Sundays . . . so she was never at Sunday games. But this was cleared in advance with the coach.
And then of course there's the challenge of managing multiple children's schedules . . . because eventually you'll have a conflict and you and hour husband will have to divide and conquer. I feel really bad that my 5 year old is going to miss her dance recital because my 13 year old is playing in a soccer tournament in San Antonio that weekend. But she is 5, and I know she's not really into dance that much (will be doing gymnastics next year) and she doesn't really seem to care . . . she's much more excited to go to San Antonio!
Anyway, I'm rambling, but I just wanted you to know that we've all been there and had to make the hard choices. Good luck!