Is it possible for a guardian to accompany me through Heathrow airport?

I'm 16 and soon I'll be travelling alone to Amsterdam. I have ASD and an anxiety disorder so airports scare the hell out of me. Is it at all possible for a guardian to accompany me to my gate? Through security and all that.

You need to contact the airline for that, not random strangers. BUT I bet someone can, maybe even a steward or stewardess.

Ask the airline

Not through a UK airport. If the airline has an unaccompanied minors service, that would be your only option.

Call your airline and ask them about an airline escort pass. They will be able to tell you whether it's possible and what you need to do. Don't wait until last minute.

It is possible to have an escort.
Your PARENTS arrange it with the special needs agent of the Airline.
They call and talk to the human about your situation.

I have ASD DO NOT expect every person working for the Airline to be an expert on your situation.

Autism has a very large range of requirements. Your parents will need to make arrangements for your entire ride not just the few minutes from check in to security.

I don't think a guardian can come if you are travelling alone, but an airport staff member or a steward or stewardess probably can. I live in the United States, and parents and guardians can't come to the gate for a person travelling alone, but an airport staff member can. I'm not too sure about the UK, but as I said, I know they can't in the United States.

If you have a recognised medical condition and the paperwork to prove it, and if you phone the airport and explain the situation to them IN ADVANCE, they will certainly provide someone to accompany you through the airport.
But as far as I know, having 'ASD and an anxiety disorder' doesn't prevent you from reading direction signs or from asking at each point (check-in, passports, security) "Where do I go / What should I do next?"

The airline will provide you an assistant
you will have to request that at the time of booking
your ticket
people without tickets or boarding pass or passports
for international flights are not allowed
inside the immigration area or the gate

Most all airports provide wheel chair service. For any reason you need one. That would take you from the gate to the plane. Then from the plane to the exit. You do pay extra for this. But I have seen old lady's who want nothing more than pampered service use it. Like they say if you can pay they will provide it.

16 year olds don't need to be accompanied by an adult, if you really feel that you need someone with you to keep you calm ask the airline to provide that person.