Do you think it would be more interesting if they didn't age so fast?
For example, they go to a resort for a few days and they age, say, one year per day. For the first couple of days, they just enjoy their life carefreely, until they realize their kids have grown a little.
Their attempts to leave the beach last for days, leaving much room for character development as well as for the horror the characters feel, having ample time to realize and experience the drawbacks of every stage of ageing they go through.