Thank you for reaching out to us.
We appreciate the sensitive nature of this question.
It is perfectly normal to prefer not to encounter acquaintances at the mikveh. However, there is no way to guarantee not seeing anyone one knows.
You can rest assured, though, that any woman you might see at the mikveh would be there either to facilitate other women's immersions or to immerse herself. In either case, they would be the first people to be understanding that other women sometimes immerse and would like their privacy to be respected. While some women do socialize at the mikveh, it is also widely understood that other women at the mikveh are not there to socialize, so it is not considered rude to keep to oneself.
It is also perfectly normal not to feel comfortable with having one's body exposed in the presence of the mikveh attendant. To minimize this, you can ask the mikveh attendant to turn around until after you have entered the water (with just your head out) and only then to turn to see you dip. In this way, the water will obscure most of your body, and she will just be focused on the immersion itself. You can also request that she exit the room immediately after you dip. Here, too, it helps to remember that the mikveh attendant is there to facilitate performance of a mitzva for many woman, and takes no personal interest in seeing your body.
We hope that these ideas help. If you have more specific concerns that remain unaddressed, please don't hesitate to follow up with them.
Please let us know if we can be of further assistance.