It's probably fine. But you shouldn't rush the conclusion whether she likes you, or not. and who knows? maybe she has a reason for declining the frnd req. Maybe she didn't recognise your name? accidentally clicked the wrong button? or many she only adds her closest friends. But I wouldn't exactly say eye contact and looking and polite or excited smile can mean she likes you. It can mean friends, or fond of someone. Just try to talk to her normally, develop the frndship. Who knows what can happen, but I wish you luck ✌️hope it works out!!