I fail to see the dilemma as you've made a choice, reassurance is good tho: 2 Jobs will have you way too stressed out to perform either,the Job with the elderly is a good working environment with good money, as opposed to retail hours, stress and wages.
The job with the elderly it is!!!
Shops aren't going anywhere, trust me. So you can always return to retail in the future should you want to.
Learning a new skill is always scary, I should know, 9th job, my 9th skill,but its doable and rewarding as hell