INTJ over ENTJ. I would say I about 80% probability while E about 20%. I'd rank her strength, in terms of FFM, about 40% E.
There are far too many introspections for it to be otherwise, IMO (I am basing this on her letters. Chances are she has become more comfortable being E).
I would, however, accept any of the INTP, INTJ and ISTP axis as a possibility. I've read INTJs letters, but they are very similar to my own. The only difference is the degree in which she followed through. The willingness to change... some... indicates either a N or SP behaviour. Her approach shows more T than F. And as above, I believe she is an I.