In general, removing PTSD from the picture, if someone is old enough to be my parent, for me, that is too old. For other people, maybe that is ok.
There must be a reason why you picked someone 30 years older to invest in a relationship with instead of someone in your own generation, and then posted about it anonymously on a PTSD website.
You may feel that PTSD is not related and that this is all love. That may or may not be the case.
If you have trauma in your background, or you have been a supporter of people with PTSD, then this is actually more concerning to me than it would be for someone who had never been traumatized or a supporter of someone with PTSD.
Let me explain.
If you have PTSD yourself, and that came from abuse at the hands of a much older person, this relationship could be an attempt to subconsiously get the love you didn't get before. That's not a good or bad thing, but it is something to be aware of.
If you have been a supporter of someone with PTSD, and you are now in a relationship with someone who is much more likely than most people your own age to get sick and need your help, then I think you need to look into why you are drawn into relationships where you are needed to support another person so much.
Sufferer or supporter, if you have ever been abandoned in the past, then it might be worthwhile looking into why you picked to invest in a relationship with someone who statistically is more likely than most people in the dating pool to "abandon" you through death.
Love is not blind. Love sees things for how they are, realistically. Infatuation is blind and says death doesn't matter. Of course it does. Having the person you love die is very hard. Someone 30 years older than you is statistically MUCH more likely to die 30 years sooner and thus "abandon" you than someone who is closer in age.
If neither you nor the person you love has PTSD, then why are you asking for opinions about age differences in dating relationships on a PTSD website? Why are you asking trauma survivors and their supporters their opinion on this?
I think you need to be more honest with yourself.
If you posted saying, "hey I am in love with someone who is 30 years older and I know they will likely die sooner than someone my own age and I think it is still worth it" and etc, then I would be less concerned. It would show you have made a realistic assessment of the relationship and found it to be worth it.