Can someone else be there while I train?

Always yes. Sessions happen at your house, in your yard or at a public park, and whoever you want there is welcome. Nobody has to be alone with a coach they have just met.

It genuinely is not awkward for me. I have coached in garages with the whole family on the driveway, in back yards with dogs and toddlers going past, and in parks with half a soccer team watching. An audience of one is nothing. See whether your family can watch.

The one thing worth agreeing in advance is what that person is there for. Watching is fine. Filming a couple of drills so you can practise them later is genuinely useful. Coaching from the sideline is not, and I will say so politely, because two voices in one session is how people learn nothing.

If you would rather do the first one somewhere public, that works too: a park, a beach lawn, your apartment complex gym. Your city page lists the spots people use. Find yours.

You can also bring somebody in as a training partner rather than an audience, which is what most of them end up becoming by the second session anyway. See training with a friend or partner and training with a group of friends.

For a lot of people this is exactly what makes the first hour possible, and you do not need to explain why. If it is nerves, being nervous about a first session is more common than not. If it is heavier than nerves, say so when you message and it shapes how the whole session runs. See training after a frightening experience.