Well I don't think its something to be ashamed off. They just are very old fashioned and believe in "their house then their rules and consequences". And as long as you live under their roof, you aren't too old to be spanked. At least you have strict but obviously caring parents who Care abut how you behave and how you turn out when you do go out on your own as you will someday.
My step daughters were never too old for a good panties down spanking. My oldest was 23 her last spanking, and the younger was 22 when she got her last fanny tanning.
Its nothing to be ashamed of. Just behave yourself and try to do the best you can to obey the rules your parents have set forth. And that way, you keep those awful spankings to a very minimum.