Yet, a decade later, Voice of Baceprot's three Muslim women will become the first band from Indonesia to perform at the world-famous festival in Britain this week, where the headliners include Coldplay and Dua Lipa.
Their set will mark the latest highlight in a wild career that has seen Firda Kurnia (guitar and vocals), Widi Rahmawati (bass) and Euis Siti Aisah (drums) amass a huge fanbase while challenging gender stereotypes in male-dominated Indonesian society.
"Honestly, Glastonbury is not on our wishlist because we feel like it is too high a dream," Euis, 24, told AFP.
"(I am) half in disbelief. That is why we keep checking whether it is the official Glastonbury or if someone pranked us."
Voice of Baceprot rose from humble beginnings in a village near the West Javan city of Garut.
They won fans with their raucous Rage Against the Machine covers -- the word "baceprot" means noisy in Sundanese, an Indonesian traditional language -- and also won fans with their original material.
Then came wider international attention, including plaudits from some superstars. Red Hot Chilli Peppers bassist Flea once tweeted that he was "so down with Voice of Baceprot".
And while the group has previously played in the United States and Europe -- including at the famous Wacken metal festival in Germany -- there are nerves ahead of Glastonbury.
"Hopefully my nervousness is a reminder for me to be more prepared," said Euis.
Indonesia tour dream
Muslim conservatives in Indonesia have criticised the band over the fact that they are women, and also claimed their clothes are inappropriate.
But Voice of Baceprot have stuck to their beliefs and shot back through their music.
Their biggest hit -- "God, Allow Me (Please) to Play Music" -- has racked up millions of plays on YouTube and Spotify, and takes aim at the conservative detractors who say women should not play such music.
The band has also written songs about climate change and women's rights.
"We create songs based on what we see, hear, read, and experience ourselves," said Firda.
The group's rise has come with a hazard they had not anticipated: "obsessed" fans curious about every aspect of their lives.
Some have even showed up at their homes to try and meet them.
"We're like: 'OK, maybe this is one of the job's risks.' Our families sometimes get confused," said Firda, 24.
After forming in 2014, Voice of Baceprot played at small festivals around West Java, one of Indonesia's most conservative provinces.
They later moved to the capital Jakarta and also played online concerts during the Covid pandemic.
They have since returned to their hometown, where they are building their own studio.
Widi said the band has received "a lot" of offers to play abroad.
But as they prepare to play the biggest show of their lives at the famous Worthy Farm in southwest England, Voice of Baceprot say one of their dreams is rooted at home.
"We actually really want to tour Indonesia," said Widi. "But we haven't had the opportunity yet."
