A trust fund is an allotment of assets set aside for your benefit. It may consist of cash only. It could also consist of stocks, bonds, and real estate. The Trustee should be able to tell you what is in the trust and when you will get your money.
The person who created the trust decided how and when you will receive your money. There are trusts that distribute the assets when the beneficiary (you are a beneficiary) reaches a certain age or accomplishes certain things like graduating from college or trade school.
One of my friends is a Trustee on two trusts. Each beneficiary receives an allocation of money as each beneficiary reaches a certain age. By age 35, all of the money will be distributed. These trusts also allow the Trustee to make special allotments for such things as college tuition, a new home purchase or catastrophic expenses such as medical bills.
The Trustee of your trust should be able to explain to you how and when you will receive your money. I would not expect to receive a huge sum of money when you turn 18 or 21. Such ages are too young to give a person a large allotment of money. But if you do receive a large sum be wise in how you spend it. That money was intended to provide you with a better future.
Contact your local bar association; they will advise you and provide you with a list of attorneys practicing law regarding medical negligence.