sure it's ok BUT, BUT at what price? you must consider the price you will pay....in self esteem, in tying up your heart strings, in emotional pain, in not having someone love you BACK...and more. whatever you do, do not romanticize the notion of loving someone that will never be yours. it is not very romantic at all. it is plain silly and a waste of emotion and time.
You would be much better off investing that time and energy in learning to love yourself such that it becomes unappealing to love someone who doesn't love you. At that point you will want someone to love who also loves YOU ♥
As long as you don't stalk them.