i want to get into bluegrass harmonica what position should i use?

Both, of course. A lot songs can be played either way. Personally I feel that most songs sound better in 2nd position. I just tried Tennesee Stud and Rocky Top. They sounded pretty funky in 2nd position. I played You are My Flower and it sounds really good in 1st position. So it all depends on your personal taste, on the song, and sometimes on what harp you happen to have with you when some guitar and banjo players are jamming in their favorite key. Occasionally, some of the other positions even come in handy. You find 3, 4 or 5 notes that fit a song and they might not even be in 1st or 2nd position. I'm planning to post some tabs in the near future and I'll be including some bluegrass tunes.
Ken

I think Jimmy Fadden with the Nitty Gritty Dirt Band does a great job on bluegrass style tunes, and always in second position. hear him on the Circle album, Uncle Charlie, and others. fiddle tunes often work best in first position, exceptmodal tunes, like Old JoeClark, which works great in second position.