Problem with initialize ADC registers?

#include <htc.h>

/* Start of configuration fuses*/
#pragma config IESO=OFF, FOSC=INTIO67,PRICLKEN=OFF,FCMEN =OFF,PLLCFG=ON,BOREN=ON,BORV=250
#pragma config WDTEN=OFF
#pragma config P2BMX=PORTC0,CCP2MX=PORTC1,PBADEN=OFF,CCP3MX=PORTE0,MCLRE=INTMCLR,HFOFST=OFF,T3CMX=PORTC0
#pragma config DEBUG=OFF,STVREN=ON,XINST=OFF,LVP=OFF
#pragma config CP0=OFF,CP1=OFF,CP2=OFF,CP3=OFF
#pragma config CPB=OFF,CPD=OFF
#pragma config WRT0=ON,WRT1=ON,WRT2=ON,WRT3=ON
#pragma config WRTB=ON,WRTC=ON,WRTD=ON

/* end of configuration fuses */

void init_ADC() {
    OSCCON = 0b11110011; //16MHz internal oscillator
    OSCCON2 = 0; //off secondary oscillator

    ANSELA = 0xFF;
    TRISA = 0xFF;   //input
    LATA = 0;
    
    ANSELC = 0x00;
    TRISC = 0x00;   //output

    ADCON0 = 0x01; //set AN0 to be sampled and the ADC is enabled
    ADCON1 = 0x00; //+Vref and -Vref connected to Vdd and Vss respectively
    ADCON2 = 0b00110100; //Left justified, 16 TAD, FOSC/64



}

void main() {

    init_ADC;
    while (1) {

        unsigned int adc_eqn;
        float voltage;

        //ADC start
        GO_DONE = 1;

        //wait for ADC to complete
        while (GO_DONE) {
            continue;
        }
        //retrieve adc equavalent value
        adc_eqn = ((ADRESH << 8) | ADRESL);
        voltage = (adc_eqn * 5.0 / 1023);

        if (voltage > 3 && voltage < 5) {
            LATC = 0xFF;
        }
    }
}

void delay_ms(unsigned char time) //create integral number of milisecond delays, if the clock is 64MHZ
{
    char i;
    for (i = 0; i < time; i++) _delay(4000); //for 4MIPS operation or 16MHZ XTAL TODO
}