BTDT
With my oldest, his SLP stated clearly in her report that he was classical autism. We took him to a developmental ped who said he was probably PDD-NOS but couldn't explain why. We had a psychiatrist who ruled out autism and said he was ADHD and mixed expressive receptive speech delay. We ended up with a behavioral neuropsych who ruled out autism, ruled in both the MERLD and the ADHD-HI and said there is something else going on that we can't diagnosis. We added an additional dx of CAPD 8 months later.
I force each and every doctor to give me a thorough explanation of the dx, INCLUDING how my child's exhibited behaviors meet the dx criteria of the DSM IV. I can do this because I know how to work with the DSM IV and what the criteria are etc through my job. If the doc cannot explain to me how they got their dx in a rational manner that doesn't include the terms well he acts like toher kids dx with it, well other kids I have seen dx also have this, or even more off the wall, like well that part of the dx isn't important or well we could just squeeze his hyperactivity in as a self stimulating behavior (sigh), then we take the new information we have gathered, digest it, and basically keep going and downplay that doc's dx.
When you talk about lack of empathy what exactly are you meaning? Is it that she shows no emotion or understanding of someone else (no theory of mind) or that she doesn't seem to react to other people's emotions? The difference between the two can really be hard to differentiate especially if your an extrovert type personality. Many introvert's seem to lack a lot of empathy because introverts do not gain energy from people, they gain energy from being alone. Also, many introverts social skills are below average because again, people make us (I am an introvert as is my eldest son) wore out, cranky, and at wits end. I often find myself trying to deal with people and not knowing what to say because they are extroverts, over emotional, and looking to me to feed that need and I (being the logical untactful self am biting my tongue to NOT say something to make it worse).
As for a new dx at age 14, its actually very common for the aspie label to come then. This is because this because between the ages of 10/11-15/16 is the time when social situations really start to get complex and those aspies who were able to muddle along and compensate enough with the less complex social situations will really start to fail now (hormones, romance, cliches, peer pressure, adulthood all spring up now). In fact, our neuropsych warned us that our oldest wouldn't be 100% clear of a possible ASD dx until he reached roughly 15 to 16 years old (at the time his social skill delay was considered moderate not severe, thankfully the CAPD dx and treatment did wonders for him and we aren't anywhere close to an ASD dx anymore).