I have 6 prior dui in pa, ten yrs ago, I just got another, it says 1st. Offense, can they use my past offenses against me or will it stay as 1

The short answer is yes, they can and will use them against you.  That being said if they arw more than 10 years old they dont figure into the mandatory minimum.  So its entirely possible this is a first offense for sentencing purposes.  But, the priors are added to your prior record score.  Additionally, the DA will make the judge aware of your priprs at sentencing.