He said "Pretty." Not HOT.

there is far too much to unpack here. your male relatives should not be making comments that would imply that if you weren't related, he would have a different opinion on your appearance. this may be just a "teenage boy with no filter or situational awareness" thing but the fact of the matter is that you are growing up and growing into an adult body but are not yet an adult. this is the first time where he is seeing and acknowledging you as something other than his kid sister and verbalizing it out loud to you screams red flag. the hard fact of the matter is that 1 out of 4 girls are the victims of childhood sexual assault and statistically 60+% of attacks are by people the victim knows. I dont want you to be fearful of every male in your life, rather for you to remain aware of any changing behaviors that make you feel uncomfortable or unsafe and if so, to reach out to someone you can trust. congratulations on achieving your personal milestone, and im wishing all the love, happiness and safety on your journey to adulthood

All of your other bikinis should be modeled in front of your female friends instead.

Don’t model yourself in front of your family if you are doing it for the comments on looks. Sorry, but YDI. For a male family member (or non-hetero female) there is no appropriate answer that can be given since you are asking someone genetically close to you to rate you in a bikini. Do this with your friends, or someone you believe would be the subject of the opinion that matters. Don’t ask a stupid/dirty question, without expecting a stupid/dirty answer. I’m not shaming you for being your age and in a bikini, but c’mon, your audience choice screams you live in Alabama, or (if elsewhere) a royal where your goal is to hook up with your cousin. It’s not like you just wore it and got a comment, you asked for the comments and got surprised the audience gave it. Seriously, ask friends/boy/girlfriends this. Not your brother. Failing that, maybe sister(s) or mother(s)

Nobody should make that kind of comment towards their sibling, especially when said sibling is underage.