Well I don't think you are scared of the advert...you are probably scared of the context of the advert, what is it talking about. Being scared of moths is a conman phobia...are you very scared of it or is it something that just creeps you out? Death is another whole topic on its own...that is a fear that you will overcome eventually...so don't think about it too much...it is the natural part of the the living cycle and you will come to learn that :) Hope this helped.

A courageous man is not he who knows not fear. It is he who does not let his fear master him.
<3

These are not at all irrational fears (but what is one advert?)^^"
So many people, many of them adults, are afraid of death. People are afraid of what they don't understand and of what they don't know. Regardless of how many religions and spiritual groups that have some sort of hypothesis of what happens to a person when they die, no one will ever know what it is really like to die until they do. People are also afraid of dying painfully.
There is nothing irrational about that and it's a perfectly natural thing to fear. Just don't let that consume you- you'll end up living your life as though you are on the brink of death and that's no way to live :)
I know some people who are afraid of moths, spiders, even dead fish. And they are quite a bit older than you ^^ But you needn't be afraid of moths- they're probably more afraid of you than you are of them ^^
If you want to overcome this fear, maybe start by trying to get comfortable with seeing a moth. Look up pictures online, then eventually, if there's one in your house or something, try to look at it as long as you can without backing of in fright. Eventually, I think you will get more comfortable and realize that there isn't anything to fear; but it's perfectly rational to feel "squeamish" of insects ^^
There is absolutely nothing wrong with fearing the things that you have listed and I think that nearly everyone on the planet has experienced fear of death and so many people are afraid of things like moths :) If these seem to be irrational to you, try working out why you are afraid of these things. You may find that you do have reasoning behind your fears and you may even find a way to confront them :)