Retinol vs retinoid - which should I choose as a beginner?

It's not really a matter of choosing one or the other as a beginner. Retinol is technically a retinoid, just weaker and less irritating - it's the ideal starting point if your skin isn't used to it. Start with regular retinol (or even a gentler retinoid like retinaldehyde), use it two to three times a week at night and gradually increase as your skin adapts. After a few weeks, if you're tolerating it well, then you can consider moving on to stronger retinoids like tretinoin or adapalene, but there's really no rush.