If you were adjudicated delinquent on the specific offense of "Burglary" (and not a lesser offense like "Criminal Trespass"), you likely have either 3 or 2 "Prior Record Score Points." This is because Burglary is graded as either a Felony of the 1st or 2nd degree. Pennsylvania's Sentencing Guidelines (sec.303.7) call for such Felony 1 or 2 adjudications to count as 3 and 2 points respectively. You should clarify the number of Prior Record Score points you carry with your PD, and also clarify what the suggested "Standard Range" sentence is for your current Burglary charge in the event you are convicted of it. The facts as you relay them are obviously not strong. Make certain that no additional alleged inculpatory facts appear in the "Discovery" materials that your PD will ultimately possess and share with you. You will have to weigh your exposure under the Guidelines and the strength (or weakness) of the Commonwealth's case, against whatever plea offer your PD is able to negotiate. The decision will then be yours as to whether to accept it, or go to trial.
You are asking two questions:
1) Will the prior burglary count against you if convicted? Yes it will be used in calculating your sentence and may be used to impeach your credibility if you testify.
2) What are your chances of " beating the case" It is impossible to answer this question. There are just to many facts that we don't know. Even if we knew more it would be irresponsible to suggest a certain chance of beating the charges. You can never reduce your potential outcome to X% There are just too many variables.