As a professor and mother of three college graduates, I have to confess that I just love commencement ceremonies.They are a unique milestone in our lives, because they celebrate past accomplishments and future possibilities.To the parents of the Class of 2015, I can only say the moment has finally come.Having once been in your position,I expect that you're thinking with some amazement about how short the interval is between diapers and diplomas.To the students, I say congratulations.In order to reach this day, you had to pass one of the most difficult tests of all: surviving a truly wicked Boston winter.Now that you've all thawed out, you will soon realize that graduation is one of the five great milestones of life;the others being birth, death, marriage and the day you finally pay off your student loans.Today is a time for celebration, and for looking back and admitting thatall the hard work of reading and writing, and studying and cramming before tests was indeed worth it.In future years, you will recall this ceremony, and you will understand that today, May 17, 2015,was the day you first began to forget everything you learned in college and graduate school.