The last bus leaves at eleven o'clock. It's about eleven now, Hurry up!
Is 'about' fine in the sentence? To me it is. Thanks.
It's OK generally but in the context you have used, it would make more sense to say "It's nearly eleven now. Hurry up!" "About eleven" could mean it's anywhere between 10.55 and 11.05 (to me). "Nearly eleven" means "Just before eleven". If it's after eleven o'clock, there's no point in the person hurrying up. They've already missed the last bus.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.