Zeus has a good point. you can get checked for thyroid conditions which are another possible cause of hairloss (though generally it wont be in the male pattern baldness pattern).
It can be a good idea to get your hormone levels checked to make sure your levels are within normal limits, and also to have a baseline so if there are any future complications, you can get checked again and compaire changes.
The amount of DHT naturally in your system is not a determining factor in the onset of male pattern baldness. People with low DHT levels can still get agressive male pattern baldness at a young age, and people with high DHT levels may never develop male pattern baldness. Its all about the level of sensitivity to the DHT.
Contrairily, the amount of DHT naturally in your system can have a significant impact on the side effects of finasteride. If you have a naturally low amount of DHT, and start taking finasteride, you leave your body with next to none, which can potentially result in serious side effects.
Getting your blood checked is a very good idea. If this is not possible, however, a crude indicator of DHT levels is your volume of body hair, as DHT stimulates body hair growth (cruel irony, is it not?). Of course there are other factors, such as Minoxidil, which even when used topically will increase body hair.