I don't know if I can trust my judgment. What should I do in this situation?
As long as your judgment is limited purely to professional matters, you should be able to trust it. If this candidate is clearly the strongest person for the job, you have a clear idea of who the best person is. If you feel that it's possible you may be overestimating the skills of this candidate, and there are other candidates in a similar skill range, you can feel free to make your decision on other reasoning, as long as it continues to remain professional.
For example, based on this:
I do worry that it might actually be clouding my perception (that perhaps she's a stronger engineer than she actually is)
If you feel that any person is more likely to bring in skills that are not strictly engineering skills, e.g. a stronger leader of a hypothetical future team, or a possible expertise with sales or client-focused interaction, that could be a tipping point.
If there are positives and negatives regardless, and you genuinely have 2 or 3 equally skilled possible employees, you can in fact present your opinion as exactly that - inform your colleagues any of these appear to be equally good. Perhaps as a team, you will feel that one is more suitable, or flip a coin, but you will absolutely have treated this potential employee fairly, as well as noted to the rest of your colleagues that there is someone else who could be approached in the future if another person of that role/skillset would make a good addition. After all, it's even possible that whoever you give the offer to first may then decline for whatever reason of theirs.