Hi Chibueze, these situations can depend on many variables, traffic, size of the roundabout, which exit you're taking etc. On a general term though I often find between 15 and 20 to be a sweet spot through many roundabout for learners. 25/30 is definitely too fast, you probably won't have time to carry out effective observation, switch lane if/when necessary or even signal if you're not experienced at that speed.
Can you put the timecode so I know which direction you're approaching from. Assuming 2nd exit is straight ahead then you don't signal on approach and left signal at 1st exit