Does it have a drainage hole? Your soil looks too peaty , get some perlite, pumice or other well draining, gritty material and mix it 1/2 and 1/2 with a cactus soil. When you pull it out of the post to replant check the roots for white or pink healthy roots, if roots are brown, shriveled or mushy take photos and repost. You could also search this list for posts about soil, gritty mix etc. and roots, rot, dead roots etc. Good luck! don;t be discourages, succulent really are easy once you have the three basics, soil, watering and the right light/sun.