I have been invited to join a skeet and trap league.
…I have never shot skeet before.
If you had been asked to join a bowling league, and had never bowled before, would you run out and purchase bowling equipment? I think not. First, you don't have enough experience to make a wise decision. And, second, you may not enjoy bowling. The same applies to Skeet shooting. Before you commit to joining a league, you might want to give Skeet a try.
I was introduced to Skeet in the mid-60s and was hooked the first time out. For some time I shot with borrowed and rented guns before I bought a shot gun. My first gun was a cheap field pump and I soon became aware of its shortcomings and sold it. My present Skeet guns are all O/Us.
Life Member of the National Skeet Shooting Association