Hi withinwalls,
Our bodies just work that way, please try not to blame yourself. I understand that it can be very difficult and confusing especially given how society tends to victim-blame and say things like "well, you enjoyed it" or "You must have encouraged it".
We are wired to seek connection, so sometimes children / youth will return repeatedly to their sexual abuser because of the few scraps of affection they get.
As for you feeling "proud in some way", I believe it's complicated and understandable
In a twisted way, I felt vaguely thrilled when molested because it meant that someone "finally saw me as desirable". and it's mixed with a lot of other confusing feelings.
It doesn't matter if your brother remembers it or doesn't think it is a bad thing. Some people rationalise and justify harm to others, or are unable to see how their actions can be harmful.
What matters is how
you feel about it - conflicted feelings and all.
I really hope you will be able to find a good and understanding psychologist to process this with.
As for me,please do not worry. I have accepted it happened to me and plan to talk with my current therapist (with whom I have good rapport) on the confusing feelings of shame, guilt, desire, liking, disgust, shock and all of it.