Toddler transition

Ellie is going through a major transition in recent weeks (months even?) to becoming a full-fledged toddler. Maybe she's been there for a while now and I just haven't admitted it...
The biggest recent change is that she's moved up to the 2-3 year old room at day care. She's still a few months out from turning 2, but the center needed her spot in the younger room and talked us into moving her early. It's been a bit of a roller-coaster. While we were very nervous initially, the teachers in both rooms offered support and tried to transition Ellie into the new room slowly. The Yellow Room, her new class, is already teaching her to eat at a toddler table, drink without a sippy cup lid and expand in her art and activities. Ellie's also showing interest in using the potty since she sees classmates potty training... and they give M&M rewards for potty use. We're excited about all of these steps forward, even as I try to hold on to any vestiges of "baby" left in Ellie.
A couple things have us worried about the move this week, however. Ellie has been bitten twice now by her new classmates. Yesterday she came home with a prominent welt on her upper thigh from one such incident. We've had some serious conversations with the teachers about this and will be monitoring. The concern over her getting bullied in the new room was a major one for us heading into the change. I hate the idea of Ellie being scared or intimidated by bigger kids. But I am trying to temper my own nerves by thinking about the growing and learning she'll be exposed to in this new setting.
Ellie's toddler attitude is also coming out in a major way these days. She's not had too many outright tantrums, but she's frequently whiny and obstinate. We've started to work in time-outs as needed and she usually responds pretty well. I am starting to understand that the discipline part of child-rearing is going to be a non-stop and thankless effort.
But back on the positive side... Ellie's vocabulary is growing by leaps and bounds in recent weeks. And she continues to amaze us with her smiles, laughs and intelligence!