These states permit 17-year-olds to vote for Trump in primary elections and caucuses if they will be 18 by November 3, 2020:

AK, CT, DE, HI, IA, IL, ID, IN, KY, KS, MD, ME, MI, NM, MN, NC, NE, NV, OH, SC, VA, VT, WA, WV, WY. Register to vote Republican. State voting dates in 1st comment.

https://vote.gov/

AC