How old is Naruto in Boruto series?
Let's say after the end of The Fourth Ninja World War, Naruto is 17 years old. Then, in The Last: Naruto the Movie, it's stated that the event occurred after 2 years.  You can rever to this https://en.wikipedia.org/wiki/The_Last:_Naruto_the_Movie.

Then sure, Naruto married after that, let's say it takes several months for marriage preparation, and Naruto married at the age of 20, and Boruto is born 1 year later at Naruto age 21.

Now in Boruto: Naruto Next Generation series, Boruto is already graduated from the academy and as a gennin. The common age of a ninja who graduated from the academy is 12 years old. Many things happen after Boruto become a gennin, and let's say his age is 13.

So Naruto's age now in Boruto: Naruto Next Generation series is about 21 + 13 = 34 years old.