Question about a school break-in? Also, will this effect my career in Law Enforcement? Misdemeanor or Felony?

We all do stupid things as kids. Never admit to anything. If it really bothers you have a lawyer contact the school and inquire as to the damages and have her tell the school a person who wants to stay anonymous wishes to pay for the damage without making any admissions. But my advice is leave it alone. When you are an adult make it up in some other way, after the statute of limitation for burglary, theft and criminal mischief are expired.