Making a boost for a spaceship with cooldown.

So I’ve been at this all day, but I’m making a little practice game that is similar to those old arcade space bullet hells, and I want a boost mechanic with a cool down timer, but can’t seem to get unity to start the charge timer. This is my current code.

:Code for moving the ship:

public string GetKey;

public float startTime;
public string currentTime;
public float chargeTime;	


void Update () {
		
			
		updateBoost();
		if (chargeTime == 5) // <=== Not seeing the change and starting the countdown for the cool down
		{
			//run the use timer.
			chargeTime -= Time.deltaTime;
			currentTime = string.Format("{0:0.0}", chargeTime);
			print(currentTime);
			
			if (chargeTime <=0)
			{
				startTime = 5;
				print("You are ready to boost.");
				GetKey = "t";	
			}
		}
		
		//Texture movement
		TextureOffset += ScrollSpeed * Time.deltaTime;
		
		GetComponent<Renderer>().material.SetTextureOffset("_MainTex", TextureOffset);	

		
			
	}

	void updateBoost(){		

		if (Input.GetKey(GetKey)){
			TextureOffset += ScrollSpeed * Time.deltaTime * 5;
			
			//run the use timer.
			startTime -= Time.deltaTime;
			currentTime = string.Format("{0:0.0}", startTime);
			print(currentTime);
			
			if (startTime <=0)
			{
				chargeTime = 5;
				print("You are out of fuel.");
				GetKey = "r";
				
			}
		}
		
		
		
	}

First time posting here, so I think this is everything I need to post. I’m kinda new at this.

public float startTime;
public string currentTime;
public float chargeTime = 0;
//Added a boolean to disable boost so you don’t have to change the key
public bool boostLeft = true;

	void Update () {
        //Removed updateBoost() and added it to update() so it would be easier for me to figure out what was going on

        //Moved this, not really sure where it belongs
        TextureOffset += ScrollSpeed * Time.deltaTime;
        GetComponent<Renderer>().material.SetTextureOffset("_MainTex", TextureOffset);

        if (Input.GetKey("t") && boostLeft)
        {
            //Not really sure where this belongs, either
            TextureOffset += ScrollSpeed * Time.deltaTime * 5;
            startTime -= Time.deltaTime;
            currentTime = string.Format("{0:0.0}", startTime);
            //Added "Boost Left " to help with cleanliness
            print("Boost Left " + currentTime);
        }
        //Changed this from an if-else to separate if-statements so they are checked individually
        //Added "boostLeft &&) to make sure chargeTime isn't constantly set to 5
        if (boostLeft && startTime <= 0)
        {
            chargeTime = 5;
            boostLeft = false;
            print("You are out of fuel.");
        }

         //Changed to ">0" just in case you want longer or shorter charge times and for another reason I forgot
        if (chargeTime > 0)
        {
            chargeTime -= Time.deltaTime;
            currentTime = string.Format("{0:0.0}", chargeTime);
            //Added "Charging " to help with cleanliness
            print("Charging " + currentTime);
        
            if (chargeTime <=0)
            {
                boostLeft = true;
                startTime = 5;
                print("You are ready to boost.");  
            }
        }
}