By default, mirroring is ON in Boomcaster and you will see yourself in video just like you see yourself in the mirror in real life. But if you don't like this view, you can change that in Boomcaster when you join the session. Just turn the mirroring OFF.
When mirroring is ON, you might be seeing texts in your background and on your clothing appearing the wrong way. But not to worry, your video isn't actually backwards. Your session participants will see everything correctly.