I am into my second year of instruction, and have now been introduced to shifting.  Starting Wohlfahrt's Book 2 and Suzuki Book 3, and Hrimly's scales.  I think 3rd position is coming pretty easy, and I was feeling pretty good about things, that is until my teacher had me try scales in positions up to 7th.  I can get up to 5th, sounds horrible of course, but physically I am able to 'get there' at least.  But 6th and 7th?  Forget it.  I cannot absolutely cannot put anything above an index finger down on the G string in those positions.  It appears to me that I simply do not have whatever it takes, flexibility?  length of finger?  I have no idea.  My teacher is standing there looking at me, saying the form looks OK, but fingers 3 and 4 are up in the air and I cannot bring them down to the string.  And after trying for just a little bit, I get pain in my arm, my hand, my thumb.  I just don't get it.  Has me questioning everything, now.  Most disheartened by the prospect of these higher positions.  I told her I wasn't even going to try anything about 5th position anymore.  I feel like this is just one of those things that an old dog with no natural inclination towards this instrument ain't gonna get.  And that is depressing.