Undertow has five age groups: U19, U16, U14, U12, and now U10 – if the player turns that age on or after the first on the current year then they are the next age group up. Ex. Player turns 16 Jan 1 of this year then they are U16 the entire calendar year. Think of how old you are when the clock strikes mid night on new years. If you haven't yet turned 12,14,16 at that point, then you are under and hence U that age. And note that for indoor we are looking at your age for 2015 calendar year.
Or simply this: Born 2005 or later = U10,
1998 or older=U19
All players are encouraged to be members of US Field Hockey, and to affiliate with our club Tidewater FHC under US Field Hockey. This is required to participate in any US Field Hockey sanctioned event such as Disney Showcase and National Indoor Tournament.