Your parents will most likely take it badly. Arguably, it's a good thing for teenagers to get into the habit of doing chores. Once you move out you'll be doing all of the chores on top of studying or working full-time.
Say yes to what you can reasonably manage. Say no if it will impact your schoolwork. If you feel the division of chores between you and your brother is unfair then discuss that with them using neutral language. For example, don't approach them with "it's unfair I do more than my brother", instead approach it as, "I think this could be fairer, for example, brother could do X, Y, and Z and I could do A, B, and C."