My mother is taking over my wedding!

Ok I’m sorry but I need to vent BIG time... I’m having a problem with my mother. Literally the day after I got proposed to, she began planning my wedding. Our agreement is that she pays for the venue, and flowers and I was going to pay for everything else. Well, I didn’t get to pick my date (because it was an inconvenience to “everyone” meaning her— it fell on a Monday) I did not get to pick my venue (because the one I fell in love with didn’t have AC and it was too expensive—but if we chose my original date it would’ve been half off...just saying) I wanted a small wedding of 50 guests (now it’s 200 guests). And now working on the decor (which I am paying for) I feel like I still get no say. Our wedding isn't until July of 2020. I like taking my time on deciding what my fiancé and I want, but my mother is pushing us and rushing us to have everything right away. She calls me everyday, sends multiple texts and pictures of what she likes and already bought. She’s already bought table cloths without my permission and hand held fans (which are not what we wanted and don’t match the original decor plan). I tried multiple times talking to my mother but she’ll take it offensive and say that “you’re not appreciating anything I’m getting for you” “fine I just won’t be at your wedding” “I just won’t be involved” (basically playing a pity party). She also was getting mad because she wanted to pick out her dress already (I haven’t even chose mine yet) and she wanted to get a champagne color and I told her not to buy it yet because (I had already told her) I wasn’t sure if I wanted to wear white. She flipped out (because she had found her dress it was “the one”-that’s what she said). So I gave in. I didn’t want to hear it anymore. When she doesn’t agree with me she’ll go on and on and on about why we shouldn’t have this or that or whatever. I just wanted a chill, stress free wedding plan. I even told her that. Yes I have been stern with her and yes I know she’s just trying to help me have my dream wedding but how am I supposed to have my “dream” wedding if I can’t even pick anything out or have a say in anything? Honestly I feel like I should just cancel the wedding and get married at the court house. She’s making it so difficult to even tell her how I feel or anything about this. I feel like just giving up, letting her do it all and pay for it herself (let her continue to make it her wedding, she compares hers to mine every time I want something different than what she had at hers).i literally have the same argument with her everyday. I honestly don’t know what to do anymore.

P.S. please no mean comments