"Be confident and don't apologize" is great advice for all of us.
Before we transition, we are basically in hiding. Some of us are in hiding even from ourselves for decades. Gradually, we stop hiding from ourselves, then from those closest to us. Eventually, we have to face the prospect of stopping hiding from the world at large. That's what social transition is: stopping hiding.
So anything small we can do, like painting our nails, to practise not hiding will train us to not hide the elephant in the room. If you can do the small things confidently and without apology, then the bigger things become easier.