Hi Asfalt, awesome first step in my opinion. Clearly, you've lurked and "worked in secret" for a long time before posting your product here at the guild. Thanks for the compliment to my never-ending-job.

Your topographical map looks alright, but way "too elevated". The very high areas (brown) are too "fat" and there is far less lowlands (green) than one would expect from a North America sized continent. AlexSchacher made a very cool colored topographical map of Earth which you can use to compare.
And by the way, how are you doing your map? Best method is to have each altitude/color in a different layer - is this the technique you are using?

As for your biomes map, how did you work those out?