Advise on how to deal with bossy mom

If I was you, I'd have a heart-to-heart with her and just remind her this is your wedding, not hers, and it is about you and your fiance celebrating your love for one another, not anything else. It is not about her, and if she does not like what you want, she does not have to contribute at all. Beyond that, refrain from talking anything wedding with her, and if she asks, shrug it off. She'll get the hint that her demands are not welcome nor are they ok. When a parent contributes, I can understand them making requests, but demanding how things will be is overstepping.

"Well it's my wedding and if you love me as a mom should, you'll just let me have my wedding."

I agree with Rachel. That’s exact how I would handle it. I will have that conversation quickly to avoid further stress in the process. Good luck!

I agree with the others about talking to her but depending on whether she is actually likely to take what you say on board, I would also pick your battles. I don't know how big or important to you the things she is trying to control are but if there are any small things she wants that you don't care about so much, maybe let her have it so you have something in the bank when she asks for something you really don't want to give way on. I've tried to take this approach with FMIL, she really wanted to do our favours and she really wanted a couple of her friends (who we don't know) at the wedding and whilst I was a little annoyed at her pushing these things so much, I agreed to them because they weren't things I really cared about all that much. FH wanted us to put our foot down but my feeling is if we let her have those things then she can't say we haven't involved her or taken her ideas on board if she wants something further down the line that is definitely a no-no.

I would tell her that you appreciate the help but she needs to be mindful of what you want