Its understandable actually. A father is supposed to be our first supporter and ultimate protector. Above all he is our "ideal", and unfortunately you missed out on that part. Thats not on you,thats on him completely, however if he found out you were alive, he might (probably) would try to step into the roll now, albeit a "tad" late, but nonetheless. Being a daddys girl is in the DNA of a lot of women, its normal.
This is a hard choice for you if you take that step towards him though, maybe using your sister as the initial go between / conduit if you choose.
If you dont, and you decide to stay on your current path, then you're safe and no harm / no foul kind of thing. However, if you decide to see what if you talked to him and made yourself known to him you will have an answer one way or another if having a dad in your life is meant to be.
