Ok, both are good decisions.
Work: the more work experience you get when you're younger, the better. I've met some of my best friends from working, which is a plus. Experience in a working environment and having a job is a plus. And money is always good, money may not buy happiness but it'll buy you cool stuff.
Lacrosse: work experience is valuable on a resume, but so are interests. I think I said this somewhere else here, but I'll repeat for the benefit of people who haven't heard this rant:
When I was choosing people to interview for a job, I didn't care about a high GPA or a lot of experience, because I knew the job entailed work that they've never seen before, so those didn't matter. What impressed me more were diverse interests. I would look at the University transcript to see which interesting courses somebody's taken, and at the "Hobbies/ Interests" section of their resume to see what interests them. By seeing what a person takes/does, you get a lot of insight into them. For example, we interviewed somebody with a minor in criminology, but not somebody with a minor in math, and we interviewed more people with a GPA of 3.5 - 4.0 than 4.0 - 4.5 (4.5 is max here).
My point is, having something like Lacrosse, Debating, Chess Club, Gymnastics, Ukranian Dance, Cooking, etc. on your resume makes you seem like more than a piece of paper, it makes you seem interesting. So take diverse interests, and don't assume that nobody notices. I did.
But I still think having a job is better