I can't believe I am asking this but I am incredibly frustrated….. it should just be a simple expression in the group node $LIFE < .1 but it's not working……….. I want to group the particles that are just being born, any help would be greatly appreciated

the easiest way to group particles that are being born is just to fill in Birth Group parameter in Source POP or Location POP

$LIFE < 0.1 or any small number works too but
- be sure to check enable in group POP
- set your lifespan or tested value to reasonable number since life is normalized to 0-1 value over the whole life so by default 100s and 0.1 is 10s so particle would be in group for 10s from birth
it's better to use $AGE<(1/$FPS) to get all particles born within the last frame
- be sure not to test your group with Color POP because it will color all your particles to the same color if no color existed before
so rather create Color POP with e.g. black and one more Color POP after operating on your group set to white