Dreams are not merely about what we saw or read recently; if that were so, we would never stop dreaming since we take in millions of impressions each day. Dreams may be influenced by something we saw or heard, but it is not correct to say that dreams are only the result of random impressions from the day drifting about in the mind. Most night dreams and daydreams are connected to unconscious feelings.
It is also not correct that dreams are usually about sex. That is an outmoded idea coming from Freud's work, which is over a century old. Freud introduced dream interpretation into psychology, but a lot has been learned since his time and many of his ideas are now rejected. The only element of sexuality in your dream is the feeling that one of the males might make a move, but in fact he doesn't, and maybe he's not even interested, which would make you feel even more that you are unworthy, not attractive enough, nothing special.
If this is a real dream or even if you made it up while awake, it can still be interpreted psychologically because it came from your mind. It does not seem likely to be a wish-fulfillment fantasy, since nothing pleasurable happens for you. You are embarrassed, self-conscious, fearful, and nervous. Not much fun.
Dreams of nudity (nudity in public, and other variations) are very common and are usually interpreted in an obvious way, as revealing insecurity about others seeing our real, flawed self beneath the mask we present to the world. Nothing very deep there. But the dream of a female among a group of males is significant. The group of men represents society, the group mind, attitudes of the dominant culture. We live in a male-dominated world. The values of our culture come from male ideas and experiences, so feminine qualities are not valued. (Notice that you take for granted that a male would make a move on you ,without any regard for what you yourself might want, and it would not be for you to express sexual desire to any of the males.) The male "ruling class" wants you to believe they are flawless as well as kind and well-meaning, accepting you as "one of them," but in fact if a woman steps out of line, or asserts her desires and independence too much, there are consequences, which could mean violence or just the social pressure expressed in your dream by your feeling that your body is judged and that you are imperfect compared with the males.
Why does the dream takes place in the shower? Usually we expect to take a shower alone, in privacy, not in a group, as in a locker room shower that guys often have to use, and certainly not with people of a different gender. It seems like you could have an underlying feeling that your privacy is invaded at home, either physically or mentally. Showering could also symbolize the need to wash off feelings of shame or guilt, the sense of being made to feel "dirty" by others' attitudes or actions. Those attitudes are present with you in the shower, represented by the males who are in there with you.
The dream takes place at home, although no other family members are there. The family is what teaches us cultural values. Unless the parents are unusually enlightened, they will just transmit the values and attitudes of the culture automatically (it could be the values of the general culture of the Western world or of the particular religious or ethnic group your family comes from). So your feelings about being a female in a male-dominated world come from home, and there's no secret about it. The fact that you are the only one of the family at home might show your isolation from the rest of them, your feeling of being apart, not like them, not understood, etc.
The dream is not a political statement, so it's not necessary to argue about the respective problems of men and women, or the good or bad points of feminism. The dream is about feelings. The same feelings could be easily noticed during the day, in realistic situations of your life. It's just the naked truth.
It's important to be self-aware in order for any change in your life to happen. Dreams and fantasies can help you become aware of feelings that lie beneath the surface of daily life. By change I mean, for example, for you to get rid of the embarrassment, self-criticism, or nervousness that is imposed by social pressures and cultural attitudes. To become the person you want to be, you have to overcome those fears, or at least be able to assert your desires and interests in spite of them.