Unless you are playing attack were you need better stick skills any real good athlete can step in and play lacrosse.
If you have good feet , good field awareness and have good work ethic to put in extra work on the wall you can pick up lacrosse pretty quick. I had a few friends who did not play until high school and they went on to play college lacrosse.
Brendan Looney did not play high school and walked on at Navy. That is rare but can be done.