I can give you some advice being new to this, and that is first and foremost most of us want our clients to have good hygiene and to smell good, as well as being respectful towards us. Maybe give some time to book a date with a provider, giving yourself time and them. Booking a few hours or days in advance can help build the anticipation and many of us appreciate pre bookings.
I also would suggest you also make the full payment, and not paying because a provider tells you that you smell bad, is disrespectful. Also if you plan ahead with showering before you show up, means you can smell good and also to not feel as rushed or nervous.
Also go easy on yourself and don’t get upset over mistakes or embarrassing things happening as it happens to us all. If something happens embarrassing with me or to clients of mine, depending on the situation I either laugh it off or show understanding of what happened. I’ve had embarrassing things happen to dealing with medical emergencies with clients. It’s life.