Hi there,
To me, the answer is yes and no.
A HbA1c of 7.2% is equivalent to an average glycemia of 160mg/dl. In these conditions, keeping it between 90 and 120mg/dl isn't a realistic goal.
90-120mg/dl is a good target if your diabetes is well under control. You'd need a HbA1c around 5% for that which takes out of the diabetic and prediabetic ranges. So it's a nice long term target, but I wouldn't think it's a good one for you right now. You'll feel disappointed if you fail to reach that target.
In my experience, one important thing with diabetes is to manage expectations. It's important not to set unrealistic goals that will make you give up. What you can do is monitor your glycemia a lot, learn about how to manage your diabetes (diet, exercise), and make a plan to reach 5% HbA1c within a few months.
It will be hard, but depending on the stage of your condition, it can be within reach.
Cedric.