Don't worry about it mate, your'e at the start of a kilted life. What you wear is all about the level of dress expected at a function. If it was a formal wear evening event I would say that you are not there yet in regards to the kit you have. but for most other times, such as where people are going to wear casual, smart casual, you have it covered, Up until formal wear you can dress a kilt up or down with shirts, ties, jumpers/sweaters, short bomber style jackets.

Most importantly is that you feel comfortable and from your description of what you will be attending, the sporran you have will be fine.