You will not always please everybody, but that doesn't really matter. What matters is that you always fly in such a way that you can get a bollocking in one piece. From the story you told, only bit that you probably could have improved was the comment and possibly the explanation. Had you said you earlier that your performance was less than anticipated, request... If no solution was forthcoming, you then declare an emergency. Either way you do as you did. Saying you would fly into a mountain to please her almost certainly p!ssed her off. The next bit is calculating your performance. I can find out my aircraft's climb performance, but it's a lot of work. So the question is, do you actually have the numbers to work out your climb performance? If you don't, it doesn't really matter but make sure that you give ATC the heads up a little earlier to allow them to plan with you in mind. Either way, you did the right thing on this trip.
PM