We need to spend our time doing something more useful
Discounting a project on the grounds that it is trivial and time wasting is an easy trap to fall into. The thing is, that little voice is still nagging you, isn't she? Even if you avoid your project in favour of something practical (like the laundry, shopping around for a better insurance policy, or some other tedious, grown up, but very 'useful' chore) you are not fully present to it. Part of you can't shake the doubt that you are letting yourself down. Is this thing going to be on your list till the day you die?
We could, but we don't have the right supplies
Ah yes. You would start that novel, but you just need to wait until you get a new notebook from Typo.
You already have all you need.
Just start. You will be glad you did.
We are a bit old for that, aren't we?
So is that it then? It's all over? If we didn't start this thing young or get it out of our systems before we grew up it's too late?
Did ice cream stop tasting good because you stopped being a child?
If it was fun then, it is probably still fun now. And it is never too late to learn something new. Better do it today, because tomorrow you will be even older...
We are not very good at that
Now we are getting to the heart of the matter. This is fear.
We tend to think that we will be judged, scorned or humiliated if we attempt to do something that we are not totally adept at. This still seems to be the case even if we are doing something totally private like drawing in a sketchbook that we have no intention of sharing. We are protecting that inner child from criticism. But we are also eliminating the chance of new experiences and the acquisition of new skills not to mention the fun you might have in the process.
We are not really 'creative'
Oh yes we are. Just look at how many imaginative excuses we came up to avoid having to face our fears and do this creative project (which we actually really want to do).
No matter which one of these excuses you tend to use, or how many you combine, you have not managed to dismiss that little voice. So you may as well just heed that creative calling.
Life is finite.
Don't miss your chance to do these things that you can't stop thinking about.