Is This Relationship Going to Work Or Not?

Ok, so ive been seeing this girl for a month or so. We've known each other for about 6mo. We work together. Thats how we met. She had had the same boyfriend for something like 3 yrs. She would talk to me about him from time to time. My first impression was he wasn't treating her right but I never really said anything. One day I told her I think she could do better(I was talking about me) So one night we made plans to hang out. Well we gave into temptation. She did still have her BF at the time but it sounded like he was a dick and they were on the out's anyway so I didnt feel to bad. 3 days later they broke up. We started hanging out more and more and within about a week we were what we both considered a couple.

Her 'best friend' is a guy who happens to be her ex's best friend. Her living arrangements feel thru and she is now going to move in with the 'best friend'. Due to the fact we have only known each-other for a short time and our pets not getting along we feel moving in together isn't in our best interest. When we're together she is contently getting txt msg from either her best friend(the guy) or the ex who she says they only txt each other. This really makes me feel uncomfortable and insecure. My mind can't get over the fact that when she's not with me she is with her 'best friend'.

Let me state that their is a big age difference. Me being 15yrs older. Our relationship is kinda a secret due to our working together. Im not sure if the ex knows about us(its really none of his business anyways) and she claims she has told best friend about us and he could careless.

A few weeks ago another employee showed me a txt msg she sent to him. She was having people over and invited him which I had no problem with until I saw the msg that said 'I cant wait for you to come over'. Being insecure I took it like I think most guys would have taken it. "I cant wait for you to come over wink wink'. He took it that way too I think as he commented to me that he thinks she likes him but he doesn't like her and she bugs him.

I called her on what she said to him and she denied it. I finally told her about how I got the info and she admitted it and said she just ment she was excited for him to see her new place? A week later she was supposed to come over but backed out at the last minute. Said she had plans to goto her grandma's. Her grandma live like an hour away, she called me at 8 and said she was going over there. Well at 9:15 she called and said she just got back.(Math doesn't lie). I called her on it and she told me she lied. That the ex and the best friend came over to her old place and helped her move some of her stuff to the new place. Again, I went off and told her its hard to trust her when she lies to me. She told me she was sorry and from this point forward she would be %100 honest with me as she loves me and can't imagine life without me? She is always txting or calling me telling me how much she loves me and cares about me and can't wait to see me. She really has nothing to gain by telling me all this but for some reason I think she may be being un-faithful?

Id like to add that I really really care for her and want this to work more than anything. I am super super close to my family and tomorrow we will be going over there for the first meet. I told her that this is extremely important to me. I told her that if she isn't serious about our relationship that she needs to tell me now cause meeting my family is a big deal to me. She assured me that she wants to advance our relationship and she's ready to meet the family.

Am I over-reacting?

Thank you!!!!