Not to worry shellywill! Parkinson's Disease is not hereditary. :o)
Unfortunately, this is an older view--prior to enough scientific research done to corroborate the congenital possibilities.
Parkinson's and Epilepsy as well as other neurological manifestations are linked to specific genes and indeed inherited. I would encourage readers to follow information on this site (among others): http://www.genome.gov/10001217
In the meantime, if one is "scared", get scans and early diagnosis if possible, learn the facts, and enjoy life!