OK I suppose this is probably perfectly normal, but I am amazed at how fast my baby just became a regular toddler! In the last week or so, right at 17.5m, she has suddenly started having a lot more frustration in various contexts and even having tantrums on the floor sometimes. She's still very sweet and affectionate and playful, but she also cries a lot more and at things that never seemed to bother her, and almost seems to be looking for opportunities for disagreements, if that makes any sense.
I can see she's trying harder to solve problems (both social and physical), but she gets so frustrated when she can't do something and just yells and keeps trying and gets mad a anyone interfering with her goal. She's been fighting over toys etc with other kids too (or maybe more like standing up for herself around bigger toddlers), and getting her own ideas (heaven forbid ;) !) and trying to argue with us, e.g. to take the car when we're going for a walk -- she tells us with signs, then throws a small tantrum when she realizes we aren't changing the plan. Along the same lines, she's now routinely refusing to do things we suggest, and saying "no" every time we ask her a question, even things she always says yes to, even when the answer is objectively yes, and even when she actually means yes, which she shows us with her actions. Is she just trying out "no" or are we missing something important here?
We do a lot of communication (bilingual household, lots of books & commentary, baby signs) and while she doesn't have many words, she understands us both and interacts a lot, and we're used to suggesting things / asking her questions and getting pretty easy or even enthusiastic cooperation (with the exception of when we interrupt her activities for something like a diaper change -- this was where she first started saying no, even to questions we knew the answer to like is there poop in your diaper). It's funny to us because she says "no" pretty cheerfully most of the time, and we simply haven't adapted to this and found ways to rephrase things like "it's time to..." instead of "do you want to..." or even using a question intonation, which now elicits "no". I guess another problem is how to motivate her to do a boring thing (e.g. getting dressed) when she also says "no" to the fun thing that she knows will follow (going outside).
So I'm hoping for some perspective or ideas to help her (and us!) with this phase of asserting herself more and challenging herself (and us!) more. Of course I'm glad to see her standing up for herself but I think maybe life just got more difficult! Did other people experience this, and what helped you the most with this transition?