Sounds like night terrors! They can start suddenly. The late falling asleep thing sounds like low melatonin, which my kid seems to have genetically too. But she's getting more normal over time, she's 32 months now.
You could put in a call to your pediatrician. If it is just night terrors, it's pretty normal, and it will eventually stop.
Just don't try to cuddle her for some weird reason.
My daughter did the same thing, and would literally start to panic even more when I was trying to shush her and comfort her. It killed me, but I would just lean away and let her thrash a little, and pat her on the back until she calmed down again.
Another thing you could give a try: give her dried sour cherries and some warm milk after dinner, and before tooth brushing! They have a lot of natural melatonin in them, and believe me that knocks kids out, and lots of antioxidants. The dried ones at trader joes are sweetened enough for kids. The milk will soothe her. My kid knocks out after a melatonin boost and wakes up calm and happy.