Something important to consider when you start out:
Double check what "end of day" really means in terms of deadlines. Not keeping your deadline can have consequences for many people around you.
Sometimes you hear end of day and it's open in terms of the specific time, since production will show it to the client/director the next day. If you're allowed to stay late then you work until it's done. That's what I would call a soft deadline.
But there are also hard deadlines, where the cut off time could be 6pm for instance. This means everything has to be really done by the end of the day, so that production can prep the shots for a transmission with the client the next day, where shots get sent to editors, etc. There's no wiggle room, so if you don't have anything ready by 6, production won't be able to show anything and that puts them behind schedule.
There's another aspect to consider though. Let's say a supervisor asks his lead if a shot can be ready by 6pm. The lead will check with the animator on his team about that shot and the animator says he'll have it by then.
What if the animator thought that 6pm = end of day, so he/she can stay late and didn't double check about the deadline? 6pm rolls by and the shot is not ready, which is not good for the animator, but on top that it's also not good for the lead, since he assured the supe that the shot will be ready.
Be aware of the consequences if you don't keep your deadlines. It's a team effort, so be mindful of the people around you and their responsibilities.
And yes, the lead could double check as well but don't wait for other people to help you, be pro-active.