Hi J.:
I too am a first time mommy of a now 10 month old. If your daughter had been sleeping through the night well up until recently, my first thought would be that she is teething. My daughter is a great through-the-night-sleeper until she cut her bottom two and then her top two teeth. She is totally "off her game" when she is teething and wakes up a few times a night and wakes up early too. Have you tried any teething remedies for her, by chance? It can't hurt to try some baby orajel or a cool/cold teething ring. I also take a wet baby washcloth and put it in the freezer for an hour or two, take it out, dampen it again, if needed and then she sucks on it, which she really likes.
If it is not her teeth, then perhaps she is just at the age where she just does't want to miss anything. If she is super stimulated during the day, that may be the culprit. And since you said she won't take an afternoon nap, you are so right in thinking she is totally exhausted by 8pm. (I would try to put her down for the night earlier, say by 7pm at the latest and see if that helps.) When we go to family gatherings when my daughter cannot have her routine naptime (especially her morning one), and then she is up late too, she may not go down very easily that night since she has been so "busy" all day with all the fun and attention.
You are the parent. Bedtime is bedtime, and you decide what that is. You are not doing anything wrong by seeing that she gets enough sleep. I have found that if my daughter wakes up crying and fussy, she is still tired and I need to adjust to make sure she is getting enough sleep. If the crying is not from her teething, letting her cry-it-out should only last a few days anyway. She is crying anyway. If she is teething, then a little extra sympathy (you getting up in the night, holding, rocking, etc.) is ok too. Once my daughter had cut her teeth, she would usually try to stay in the up-during-the-night-mode. I knew she was ok, and simply stopped going to her when she called unnecessarily. After a night or two, she would be back on her regular 7:30pm-7:30am sleep schedule.
I hope this helps! Remember, you are not doing anything wrong just because she is acting different. :)
A. F.