What should I do about my toddler who misbehaves really badly around other kids?

My 19 month old daughter has never been around other kids, not even once besides the park so I decided to take her to story time at the library. Well, she was a complete terror! She was climbing all over everyone, tried to rip a mom's shirt, and took her purse and tered it everywhere. She tried to take a pacifier out of a newborn's mouth and even smacked another newborn's feet! Then, she fell off this stage thing with stairs where the kids sit to hear the story and she screamed so loud, it sounded like a train whistle! She was smacking people and talking really loud over the lady reading the story. I was so embarressed, I had to drag her out of there. When I take her to the park, she always has a tantrum that ends in a meltdown and I have to drag her out of the park. I don't know why she acts so mean. I never hit her or her. I guess it could be from no socialization. I feel way too embarressed to take her back to the library, I always try to avoid having her being around other kids so I don't have to deal with such a fiasco but I know she needs to be social to get used to it. Catch 22, I don't know what to do.