Yes it is the way. As said earlier all mentors agree to this and i don't think its much contradictory to not to write in the said pattern. We, the aspirants, tend to think with our limited capacities but that's the way introduction should be. The reason being that it gives preview of your essay as a whole, therefore, must be in one paragraph. Haven't you written essays or got them assessed before?

P.S. Adequacy is subject to interpretation. For now, focus on your attempt, practice writing essays.