Aye, the de jure Mali region is considered by many to be the "easy" place to start as a Muslim, as there's literally no outside threats, and won't be for some time unless the Mali or the Almoravids turn heretic.
I had my first Muslim game with a single county Bey in the Seljuk Sultante (House Baduspanid of Mazandaran, if you're curious), as I wanted to be a Persian. Pretty fun experience there, as it'll take a while for you to ever become independent, and until then its all kinds of fun wars against your liege and fellow vassals.
Really though, almost any place is a solid starting point for Muslim rulers. The only areas I'd say to avoid as a Muslim newbie would be North Africa, Sicily, and maybe the Volga Bulgars. Sicilian Muslims get squished pretty easily as they're small and very close to the HRE (and even if the HRE doesn't personally crush you, they'll gladly help the Normans do so), the Volga Bulgars are absolutely isolated and can get piled up on by both Pagans and Orthodox if they're not careful, and North Africa is infamous for getting stormed by both the HRE and France. I'm currently playing a game with a one county North African start, and the only things keeping the HRE and France from destroying me are my silly amount of alliances and my conversion to Shia (literally would've been wiped out if I didn't have the Hashashin to call in).
But really, Mali, maybe Iberia. Either way, as the game progresses there becomes an increasing chance of someone ruining your day, and both those regions will likely find themselves in conflict with the French and/or Germans eventually. Just make sure when that time comes you've established a powerful enough state to stand up to them.