I think you'll manage just fine.
From my experience, even though I'm a heavy meat eater, during the summer I kinda lose the appetite for it and prefer to eat mainly vegetables and fruits. Perhaps, your experience is similar.
Since you're doing a challenge, an experiment of sorts, and the 100 days is a long enough period for diet to show its benefits, it wouldn't be bad to do some blood tests at the start and the end of that period. That way you'll have the numbers on what the diet you've chosen is doing for you.
Good luck!
I plan to take my blood for sure at the end of the 100 days. I know it would be interesting to have a before and after but I'm too much of a pussy and really don't like needles.
I actually also still love to eat meat, it's my favorite. The conflict is too big though and It's actually not that difficult to leave it. I always knew that I wanted to turn vegetarian one day but didn't think I could do it. I once did 30 days without meat a couple years back which made me experience the difference and made it a no brainer to give it up.