If you are entering as an "undecided" major, dropping spanish won't hurt your chances at getting admitted. Most colleges actually only look for 2 years of a high school level Foreign Language, so since you've gone all the way up through 3, you'll be fine.
However, if you are doing a major like Business, where you would travel a lot, you might be required to take additional spanish classes while you are there, so staying in spanish now would cut down the classes, and by extention the $$$ you'd pay for classes in college.
However, if you are doing a major like Business, where you would travel a lot, you might be required to take additional spanish classes while you are there, so staying in spanish now would cut down the classes, and by extention the $$$ you'd pay for classes in college.