Is the battery life on my iPad good?

The screenshot graphic indicates that the iPad battery was charged to 94% when you stopped charging at approximately 2000hrs (actually 19:38 indicated in the text). Around 0100hrs, after the iPad was in use for about 4 hours 40 minutes, the battery charge had decreased to 27%.

As such, the battery charge was depleted by roughly 67% (94-27=67) in 4'40" (i.e., 4.66hr) - which equates to about 14.3% battery utilisation per hour. Depending upon the CPU utilisation and screen brightness, 10-15% battery depletion per hour is about as might be expected for a healthy battery.

In summary, on the basis of information that can be derived from the screenshot alone, your iPad battery performance appears to entirely as might be reasonably anticipated.

So, are you saying that you are actively using your iPad for 24 hours every day? The charging graph doesn't seem to indicate that. In fact, the graph seems to indicate the charge lasted close to 10 hours. Depending on what you're doing, that seems reasonable.

It doesn't matter at what point you charge your battery. It could be at 10% or 50% or 80%. Charge it when you have the opportunity to do so. The only thing to avoid is draining it completely and leaving it that way. Also, you can use the iPad while it's charging.