May be a little quick, but that is a tiny, tiny brisket and probably very thin.
There are many approaches to monitoring brisket cook progress.
One school is to just "learn" how to do it with ice picks or whatever. That is certainly a noble goal and you should get to "nirvana" in only a few hundred attempts.
The other school is to monitor the temp as you have done and adjust as needed as the cook progresses. That approach reduces the learning curve substantially and saves a ton of time, money, and frustration.
The desired end result with either approach is "probe tender" and not some temp on a thermometer!!
The thermometer is a tool to get you to the desired end result.
You are on the right track IMHO.
Keep us posted.
"Flirtin' with Disaster" BBQ Team (RETIRED)
FBA and KCBS Cook and Judge.
Former owner of a WSM, a Smokey Joe, a Charbroil Commercial gasser (junk), the legendary "StudeDera" and Sherman.
Now cooking with a Fast Eddy PG500
Proud Pellet guy cooking on real wood.