Hi Vimariex,

Hopefully I can stop you from worrying as much, as I've been in a similar situation! Firstly a biopsy is quite common during a colopscopy and I always like to think of it as them just double checking, it does not mean just because they've taken one it's going to show up anything sinister, more just to confirm it's not. 
Obviously that's not to say they nevever come back with concern, however given that you've been told you have low grade cells you shouldn't have anything to worry about. 
 

I've now been in this situation twice myself. My first smear was absolutely fine. Second smear flagged HPV and borderline cell changes, so I went for a colopscopy in which they said they didn't think there was anything to worry about but they took a couple of biopsy's anyway. This all came back fine and I was told to come back in a years time for another routine smear. This was early this year and I had exactly the same results, HPV positive and low grade cell changes, so off I went for another colopscopy in which I had either 2/3 biopsy's taken again. My results all came back okay again, so am just to go back again next year for another smear test. The whole time they detect HPV they will keep monitoring you regularly until your body hopefully fights it off. 
Just remember the aim of these screenings is cancer prevention so just keep on top of your appointments and hopefully everything will be okay :) 

Hopefully this helps! Any questions let me know xx