You are most likely fine. There could be a number of reasons for this:
1. You just haven't developed to that point yet. If this is the case, you will soon.
2. You aren't masturbating in a way tha works for you. Go to www.jackinworld.com
to find different techniques and experiment around to see if there's something that works better for you.
3. You are quitting too early. If you stop after two minutes because you can't get the orgasm, you may never achieve it. Just keep working.
Just remember, it is very likely number one is the case, so just wait and you'll develop.