Correct. 19 year old season, but is currently 20 years old, so sometimes easier to just say 19 going on 20 to avoid confusion once a player turns pro.
Most confusing is with the two international "Under-18" tournaments.
The Gretzky-Hlinka Tournament and the IIHF Under-18 tournaments fall under the same cycle, but the Gretzky-Hlinka Tournament occurs in August, before the start of the season and the IIHF U18 occurs in April, at the end of the season. But they're the same cycle of players, aka the one in August, 2023 is for players born 2006 or later, and the one in April, 2024 is also for players born 2006 or later. This always feel slightly counter-intuitive, as at the August tournament, you'd have players born August-December that are still 16 years old at the time, that are at the maximum age for a U-"18" tournament, and then in April you'd have players born January-April that are already 18 years old at the time, eligible for a "U"-18 tournament (emphasis on the quote placement for each).
Also feels fairly confusing (at least to me) when it's the same age restriction of a tournament, less than 4 months apart in time, but the one 4 months later is actually for the year below (because it's really meant to be one that's 8 months earlier, not 4 months later, if you know what I mean).
So you'd have a relatively small number of players that theoretically could play in both that are 17 years old at the time of both tournaments, the age you'd expect the oldest cohort of players to be. Different from the U20 World Juniors, which have the same Dec. 31 cutoff, but since the tournament occurs last week of December/first week of January, the oldest cohort of players generally are 19 years old throughout unless they literally celebrate a birthday during the tournament.