Kids I wish you a long life in good health. But you cannot take the cause for granted. This means eating sensibly, watching your weight, taking regular exercise, not smoking, avoiding drugs, and drinking in moderation.
I've not met a sporty type that hasn't suffered injury - sometimes life-changing - and that includes cyclists. But I wouldn't have you smothered in cotton wool - go rock climbing, scuba diving, bungee jumping if you must - just carefully weigh the risks.
Resist invitations to distant beach parties by iffy-looking characters; forgo the chance to race round mountain roads on clapped-out, hired motor scooters; and don't jump from hotel balconies into inches-deep swimming pools.
Never be led by others into risky escapades; always think for yourself. Like Joni Mitchell (search her out) says "you don't know what you've got. Till it's gone." Nothing more so than your health.