You can't make soap out of baby oil. Baby oil is mostly mineral oil and fragrance. Mineral Oil can be used on molds to help release it but you can't make soap with it. Have you tried meld & pour soap for starters? You can either purchase it at Michael's or Hobby Lobby. It's not top quality but it's good start. Otherwise you can purchase it from many soapmaking suppliers.
But, seriously, all the advice given so far is spot on. You can't use mineral oil to make soap. Lye does not saponify any kind of petroleum product, so mineral oil will just stay as mineral oil.
One could use it as a superfat in soap, I suppose, but you run the risk of low lather and an overly soft soap. It probably is best in a lotion, if you really want to include it in a handcrafted product.
Mineral oil is inexpensive and it forms a decent barrier film on the skin. That's why you see it so much in commercial skin care products -- cheap and effective. But many vegetable and animal fats also form effective barrier film AND provide other benefits to the skin. Even though they might cost a bit more, why not use them instead?