Am I wrong?

So my husband and I agreed after I gave birth that I would get my tubes tied. He said if I didnt get them tied he would get snipped and I was fine with that. Well I went into labor early and gave birth. The doctors are willing to tie my tubes but now I'm second guessing everything. I'm 21 (soon to be 22) and now have 3 kids. (3yo and twins). I'm nervous and don't really want anything else done on me. I told my husband I would get an IUD but I'm not sure if I'm ready to get my tubes tied and I'm struggling with it. I mentioned it to my husband and he is now irritated over it saying he doesn't want anymore kids and that whatever happens is on me for backing out of the agreement. I'm unsure of what to do. Am I wrong for backing out and second guessing everything? I dont know what to do. I dont know how to explain how I feel and my husband is just getting more agitated and annoyed.