When did the terrible two stage begins?

My toddler is 18 month and well she has been very hard to handle for the last few weeks and I am scared this is just a beginning! She is overly attached to me and won’t eat anything we offer unless it is bread, puffs, pasta or something she should not be eating. If she doesn’t like something she stomps and cries with her mouth wide open and tears pouring everywhere… I can’t take her crying seriously anymore but I am getting so frustrated with this behavior.