One of the main characteristics of Agile is to do short iterations. And get back to re-assess. You run ahead to explore new territory, lean from it, and then make a plan. That way your plan will be better. And if you fail (find your course idea does not work), you will have "failed fast", which is good.

So your approach is just fine. The danger though is then to say "Nice, it works, I'm done. What's next?". You're not done, there is plenty of cut corners to straighten out and you should get/take the time to do it properly once it is clear your approach yields a working and workable system. That could be to write tests, document, StyleCop, optimize, educate collegues about what you did and how you did it, have it reviewed, et cetera.