I know that question sounds really stupid but I've been picking at my fingernails forever and this year is the first time I've actually let them grow for more than a month. They are double the length they used to be, so the time is come for me to cut them but I don't know how.

As you can see in the attached pic, a lot of the nail is just dead nail (white). So if I cut my nails right down, my nails would be pretty short again. Am I never going to have naturally long nails? Or will the nail plate thing grow longer once my nails have accepted they're not going to be picked at constantly? My thumb nail broke the other day and it looks too short now... I never thought I would say that. The shortest nail I've ever had was my left little finger nail, it was 3mm long. When I began growing my nails at the beginning of August the little finger pictured had a nail length of only 4.5mm, now it's 1cm lol. So yeah. Basically I just want to know how to safely cut them before the all break. I have filed them a bit, but not much. Perhaps it would be better going to a manicurist to be told how best to look after my nails? idk.