Yes, it is normal. Block creation is random. Sometimes it'll take more time than your target, and sometimes less.
Think of it as flipping a coin. You can expect tails in... hmm... a bit more than 1.5 tries I think. But if you try it, sometimes you'll get tails in just one try, and sometimes it'll take 20 tries. But the average will converge to about the expected if you try for long enough.
By the way: I see you are forking with the existing Monero chain. If you do not start your own chain, you are a bad person. See How can individuals safeguard themselves and the community against a key reusing fork? for details. I misread the hash rate, this looks like a new chain, all good :)