I'm mad at my parents for having me and my sister at such a late age.
Why would you be angry at your parents for having you later in life? You do realize the alternative is that you don't exist, right?
My parents are so old and out of touch, I can't take it anymore.
It is wrong of you to be angry at your parents for aging. Getting older is a normal part of life and you should accept that.
No! They are old and they need to stop having sex with each other, I even got another sister.
I think most people would say it's healthy that your parents have an active sex life. Of course, you probably don't want to hear about it! Just try to understand that your parents are regular people who have normal needs, thoughts and desires.