My family doesn't know!!

I Am pregnant with my third child and only me and the father know. I live in a basement apartment in my moms house and things are kinda grim, I haven't told my family cause I'm scared of the ridicule. I lost my job and things are hard but I'm managing. I'm 19- 2 days and have no signs of being pregnant, so it's been easy to keep this secret. Should I pretend I didn't know and suprise them when I find out next week what I'm having or just wait as long as I can?