"I", "we", these are first persons. Generally, they should be avoided while writing Precis. However, a precis written in first person is not wrong per se. There are varying opinions regarding this. For example, Richard Palmer, author of "Write in Style", mentions in his book that writing in first person is actually preferred in his opinion as it maintains clarity. Similarly, Exploring the World of English also allows writing precis in first person at least at one place.

That being said, it is always preferred to write precis in third person as this is the standard manner. Nonetheless, if the text is validly paraphrased and all the points have been inculcated, there are good chances that the examiner will not discard the precis solely on this rather disputed technical point.