Is it too fast? Was using a SLYNYRD tutorial
The text appears to be well-written and clear. However, when uploading your pixel art, it would be beneficial to resize it to a larger scale (in this particular case, about three to four times larger).
Knowing the type of explosion you are aiming for can also aid in the process of choosing a speed. To view what a few different speeds would look like you can right-click the play button to adjust playback speed (preview only).
To get that result change the milliseconds each frame takes up (which you get by right-clicking the top box of a frame).