Well done!
Please bare in mind that this data is not actually accurate though - the timeframes will be a minute or so behind in some cases and the true value of the market would fluctuate depending on which is the target exchange. Previously, during my crypto-exploring days, I saw price differences between exchanges reaching 10-11% - not as a one off either.
If you create an account on almost any online exchange they have a public API which you can plug into for free and gather data from the source - if you wanted to take that as a next step. I can't remember how many of them allow historical records to the beginning of time though.
With respect to the user experience the ability to select the exchange would be good as well as fetch data between dates and/or times.
As a final thought you could begin to look into machine learning and figure out how to do time-series analysis on the data to predict the future..... lol.
Have fun!