First find how old Bethany's sister currently is: 16 years - 5 years = <<16-5=11>>11 years
Then find how old her sister was 3 years ago: 11 years - 3 years = <<11-3=8>>8 years
Then double that age to find how old Bethany was three years ago: 8 years * 2 = <<8*2=16>>16 years
Then add 3 years to that number to find how old Bethany is now: 16 years + 3 years = <<16+3=19>>19 years
#### 19