overthinking the thinking

I cant count the number of times I have now typed and deleted how to write what I need to write. I am looking for words that cant be put into sentences that actually make sense. And to top it off, putting this where everyone can see it is like screaming I need help. And as a very wise woman would tell you, I try to help everyone else, and have trouble letting people help me.
When you get into a relationship with someone who has a child you THINK you know what you are getting yourself into. BUT YOU DON’T! Every experience is different from the last. If you are allowed to be involved or not be involved changes. Your advice is used and un-used and you become the friend and the enemy all at the same time.
Today, I am not sure what I am. I have no idea if I am the enemy or the friend. I want to look for a class on how to be a good step parent and get certified so I can say “See! They told me that I know how to help raise a child! SEE! I didn’t have to give birth to see what is right and wrong or healthy or unhealthy for them!!! SEEEEEEE! I can help!!!”
I have said it before, being a step parents sucks! You are the new kid on the playground no one wants to HAVE to pick for kickball. Because no one knows if you are any good at it and you don’t have an example of the things that you are good at, so you get picked LAST!
And the even worse part is that you can see everything happening, you can talk about everything happening, you are part of it and it affects you! But you still ARE NOT THE PARENT! I feel like lately, because of the game of tug-of-war we are playing, that I have to walk on egg shells before I can help pull for either side. And in this case, I am not sure what side I should be pulling. I know the team I am on, but one day we pull from one side and the next we pull from the other. Not to mention how many other people are involved and pulling too. UUUGGGHHH!
The even worse part, is I have nothing nice to say anymore. I am pissed! I am mad. And it isn’t at just the adults. When I am spoken to, when I am in view of, the things in my head that I want to say, that I want to yell and that I want to make clear I CANT!!! Because I know that it isn’t me who should say the things.
And when I really think about it, and I mean really over think it. I start to question myself. I start to wonder if the reasons I think things should happen, are because I think that I can do it better and want a chance to prove it just because. I start to over think if that makes me a bad person, friend, step parent, girlfriend. You name it. I am not questioning everything. Is it really any of my business until it happens, should I just be listening when someone needs me to listen, should I be saying anything at all? Am I doing this because I want to or because I have to, am I this upset and frustrated because I should be or because I cant be?
I am just feeling like, everyone has picked who they want on their team, and I am the kid that has to sit and watch because the teams wouldn’t be even anymore if I joined in. I guess until then I will just hold up my teams flag and cheer for them, whatever team that is.