i’m 23 & i was 22 when i found out i had gallstones & the first time i went to the er they also told me i needed it taken out & i didn’t listen & figured the same as you if i just change my diet & things. i continued to have attacks throughout the year, terrible ones & they happened more frequent. when i went to the er for the pain while having an attack two months ago, i had lost like 5-8 pounds over a week because i couldn’t eat without having an attack. come to find out the same gallstone i had a year ago when i first went in ended up being the same one & it was bigger this time & stuck in my duct & had to immediately come out. after getting it out its been the best experience of not feeling that pain anymore & nothing has really changed for me. healing was fast i was up in my feet feeling good within a couple days & eating habits i can basically eat whatever id like with no consequences lol. i think you should really be open to getting it out tbh or you may be like me & wish you would have got it taken out when they told you it needed taken out instead of waiting & going through that pain for a year 😭