Women have a great sense of humor if someone is watching her and here you are sure that she knows about you watching her all the time. She must be aware of your intentions too but she did not act on it because you have not taken any step towards it. There is no indication from her end that she is interested in you so be careful while approaching her otherwise, you will end up losing your respect in the family and you would have no explanations to give it to your family.
If your gut feelings are saying that she is interested in you then send her indirect hints that you would like to be intimate with her and see her responses. If you find her response positive then you can take bold steps to approach her but before doing anything you should try to know her mind.
Women are more concern towards their desire and very particular towards their selection of partner whether it is single or multiple. In this case you are assuming that your aunt is inclined towards you for sex but dear how you get confirmation? Whether she has given any indication? These are serious topics that needs to be taken seriously and casual efforts may be dangerous.
You have to come closer in words towards your aunt and share your idea of innovation in relationship. If she shown her interest then nothing matters. There are cases in which elder women are involved in sex with the young. You have to take the discussion route to resolve the illusion in your mind.
She might be aware about your activities but your message has to be reach her directly so that she will reply you in a better way that would give you a reasonable solution.