It's completely natural to be nervous about your first times out in public in a kilt. The great thing is that most people just ignore it. It's just like when a lot of guys started wearing earings or when getting an elaborate tatoo became popular - people get used to seeing you in a kilt and there are no comments behind your back. Most people ask very polite questions. My first couple of times out on a regular day included getting gas and stopping at the Post Office and drug store. Enjoy and be happy with the experiences.