In the west we tend to say your an adult at 18 (yet in US can't drink til 21)... but really 21 makes much more sense. What I don't like is that 21 is an adult for a male here and 25 for female. For instance a 24 year old female needs parental permission to marry yet a 21 male doesn't. Not quite right on that especially as women tend to mature faster.
I fully support the Philippines for not allowing vulnerable young girls going abroad to an uncertain future (even though little is done about the many OFWs who go abroad to be abused in all sorts of ways) .... BUT, this is not a country of free movement for its citizens.