I am a half ashkenaz half sefardi baal tshuva. I realize that since my father is ashkenaz then I should take on his customs. However, my mother was much more observant and traditional when I was growing up so I naturallly began observing sefardi minhagim and I am often more comfortable with them. my father couldn’t care less which ones I followed. since they aren’t very observant I hardly even know what thier family customs are. is it such a big deal which minhagim I choose to follow? don’t many sefardi baal tshuva take on chabad customs and other customs not familiar to thier homes? I have always put teffillin on sefardi and eaten beans on pesach but now I’m all confused as to what to do.

All other things being equal, children normally take on their father's customs, but this is not a hard and fast rule, especially among those whose parents were not observant. In your case it sounds wise to continue with the customs of your mother's side, especially if you are comfortable with them.