Snake venom is more powerful during adulthood at one to two years, but poisonous snakes can control the amount of venom injected for each bite. Baby snakes often inject all of their venom upon first bite, so a higher dosage is more lethal compared to a partial dosage.
Studies have shown that snakes have control over the amount of venom they release and tend to release more venom in higher stress situations. Adult snakes tend to have higher control in regulating dosages, and that often leads to higher success rates of fending off predators. There are disadvantages to the snake when all the venom is used.