Authoring practices differ a lot across scientific fields. In medicine or biology, the list of authors may include people vaguely related to the paper, to say the least (see * footnote below). Therefore, some ranks in the author list can be considered as important: first, last, second, second-to-last, third. Those who fight for such a meaningful ranking (cough-cough) often accommodate well people in the middle who don't modify the ranking.
To complete that list, the end of the paper sometimes contains contributions: X wrote the paper, Y designed the experiment, Z did the stats...
It does not matter whether you want to pursue academic honors or not, now. And maybe later you may change your mind. This is a question of scientific integrity, and if you were said to be included, this is well-deserved. If you did not do enough work to be included afterward, you should be said so as well. No surprise should reside among authors and their order. Even if for some reason (you cannot endorse key aspects of the paper you would not be listed) your contribution should be acknowledged: in the acknowledgment section, or a footnote at least.
In case of a blatant mistake, changing the author list is doable. In my experience, we had to remove one.
(*) In bioinformatics work I had been involved with/informed of, it was requested (by contract, apparently) that the bio-sequencing would have x persons set as co-authors, some who (one sometimes suspects) would even not read the paper before submission. What a contrast with mathematics, where people are usually listed in alphabetical order, being expected they all had contributed equally to the paper and endorse it totally (yet, there could be mistakes still).