So I just got engaged 2 months ago and just last week my sister got engaged!!! Do I have every right to be upset/mad?? And my mom is helping her already plan hers and my wedding is before hers? Am I over reacting/getting jelous? Or is it just me!

If I were you I would be upset too. Are you and your sister close? I think this would be a great opportunity for you and your sister to bond. As long as you two are doing your own seperate wedding themes, ideas, colors, etc... why not plan together? When one starts copying the other, then there might be problems. If you don't like the whole plan together idea, make sure you are letting each other know about major parts so there aren't any doubles. Like the same dress, colors, father/daughter dance song, etc.... best of luck.

I don't think its horribly wrong of her.... however; I do think the wedding should be at least 6-9 months after yours!!!
It would for sure be hard to not feel like throwing that "HEY IT WAS MY IDEA FIRST TEMPER TANTRUM" cuz I know I would be horrified....but from the outside looking in...I would make sure hers is plenty far down the road so the attention is focused on you, your day and not the stress of parents hurrying to get through yours- cuz their is a second one to plan.
I feel bad for you but hopefully it can work out for the best....and like the other post said, maybe ya can help each other and feed off each others ideas. Good luck and hopefully thing will calm down and things can be all about you as it gets close to YOUR day!!!! I don't blame you for havinbg the feelings you are. Hang in their.
Good Luck girl.