What you need to do

 ’Tis better to have loved and lost
Than never to have loved at all.

Alfred Lord Tennyson, "In Memorium: 27"

Take a chance, be involved.  

Try not. Do or do not. There is no try.

Yoda, character in Star Wars: Episode V—The Empire Strikes Back (1980)

Do all that you can.

Be a realistic optimist.

All genuine knowledge originates in direct experience.

There can be no knowledge apart from practice.

Mao Zedong, "On the Relation Between Knowledge and Practice, Between Knowing and Doing"

You must be involved.