Do you mean you haven't been able to make yourself throw up, or you've never thrown up?

It's not good to make yourself throw up, in most cases, unless you've been poisoned (and only certain types of poison, I believe). So, being able to might be good in that case, but in general, it's not.

If you've never thrown up (like from being sick), that might not be a good thing, since throwing up rids your body of things it feels is harmful to you. Or maybe you've never had anything inside you that would cause you to throw up, but I would consider that unusual. If this is the issue, you might want to consult a doctor to see what s/he thinks.

But on the making yourself throw up thing, don't feel bad. I've never been able to do it...mostly because I chickened out! I tried it when I was a kid, not since then, trying to fake sick to get out of school! If I start to feel that sensation, I start trying not to throw up, LOL!