You will have to list all the trips in the last 3 or 5 years when applying for for N-400. Listing countries like Cuba, Syria, North Korea etc etc will at minimum put you in extended background checks, requiring much longer process. You may also need to do some explaining to CBP and other authorities upon return to the US.
Travel to Cuba is frowned upon. If you're a US citizen you'd have to apply for special license in the US to travel there.
My recommendation is to not travel to Cuba. Unless you have sick mother there, do not put your future at risk.
In short: yes, I believe it can slow down and affect your I-751 and N-400.