how long is long enough to leave henna on?

hi! my sisters and I did henna on Christmas, they used one brand and I used another - I think the one I used was not the best quality because it looked more like it sat on top of my skin (like a sticker) rather than in my skin like my sisters. The stain only lasted like 5 days for me before rubbing off. My sisters held up well and still look good 6 days later and they only kept it on for 2-3 hours.

I’ve redone my henna today but I ended up taking me SO long so I finished it at 12:30am. It’s now 4am and I want to take it off so I can go to bed but is that going to be long enough?

I used to get henna done a lot when I was younger at fairs/festivals/markets and sometimes my sister would do it for me but this is the first time I’ve done it for myself. The first pic is what’s on my hand now and the second slide shows my first 2 tries. also Ik there’s a lot of smudges I’m still learning!!