The pressure from a massaging shower head is safe for anyone. You should, however, never leave small children unattended in the shower or bath.
Other Shower Head FAQ's:
Shower caddy rust stains on my shower wall? What should I look for when purchasing shower heads? I have very dry skin, should I limit my time in the shower? Are there benefits to having a ergonomically designed shower head? Are massage shower heads safe for little kids?