My only regret is that I didn't get to stay around long enough to fight radical Islam.
Went in just after my 18th birthday in July of 1964. Spent 10 years active and 17 reserves. Went to OCS in the Army in 1966 and retired as a LTC in from the Reserves. Served in VietNam and would still be in if they didn't think I was too old. (almost 60) Go for it. Best think a young person can do.