Jury service in NZ

I’ve been called up for jury service for what may be a two-week trial. Wondering at what point they actually choose the jury? Is it on the first day? Just wondering if there is a chance I won’t get selected as I volunteer for two not-for-profits that help at risk youth and those coming out of prison. I’m so busy with my own full-time work outside of this I’m kinda hoping I don’t get selected but also would like to be part of a jury trial and see what’s involved. Any barristers on here? Would my volunteer work mean I’m less likely to be selected? I’m sure I could keep an open mind as someone who has been a victim of crime and also seen the impact of our justice system on people and their families (both victims and perpetrators).