No wedding date set but bride still wants a bachelorette party

So my best friend recently got engaged and they were talking about a December wedding but did not have a date set. She asked me to be the maid of honor and asked 11 other girls to be bridesmaids. Before her and her fiancé did any planning the bachelorette party was discussed. She bought tickets to see a band play in Vegas in June. This same weekend happens to be my 30th birthday which I desperately wanted to do something for because it's a big deal to me but now instead I have to plan and attend a bachelorette party with a bunch of strangers and see a band I hate rather than celebrating my 30th with friends. But I'm getting off subject. The thing is that now she's saying she thinks they're maybe going to have the wedding next April instead of December. But they have not done any planning and they don't have a date. Should we still go through with this bachelorette party when no wedding plans have been made yet?