What do I do to get them to stop picking on me, and taking my coworkers side ?

Every where you go there is someone who has problems and just can't work well with people unless they have someone to pick on. You must give off some vibe that you are an easy target. You HAVE to change this now because unfortunately you will meet these giant 3rd graders where ever you go. They feel inferior and unfortunately working with them feels like you are in middle school again. I be she's older than you right? Totally sad. Anyway, you need to start dressing really professionally so that you feel confident, wear heels and makeup and make sure you KNOW you look good every day. If you know you look good, you will feel more confident and you will act that way. Bring some reading material that is rather technical that you understand or something similar and read it in front of them. Don't react to them at all. Be sure you act really confident in front of her and don't act weak or timid at all. Believe me, she will find someone else to pick on, this works. You will have to keep this up so that she will learn she can't get to you anymore.