As long as you are “clear” about your intentions (which it sounds like you are), don’t worry too much what others are thinking or not thinking. Your intentions seem genuine, clear and honorable to me – you are helping your father sell a property. If someone is confused or curious about your intentions, let them approach you (like your friend did), and then you can respond to their comments or questions.
As for people thinking that your outfits are fake, that’s their concern. If you are happy with your outfits, then that’s all that matters. People may misunderstand or judge you, but the most important thing is for you to be okay with yourself. You sound like a responsible and mature soul. Your father is fortunate to have your help and support! ~ Josh