Modding Problem Waits

I want a delay to start just after 30 seconds in this code however nothing i tried has worked... 

package me.fennx1000.barrage.init.entities.custom;

import me.fennx1000.barrage.init.EntitiesInit;
import me.fennx1000.barrage.init.ItemInit;
import net.minecraft.core.BlockPos;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.projectile.ThrowableItemProjectile;
import net.minecraft.world.item.Item;
import net.minecraft.world.level.Level;
import net.minecraft.world.phys.BlockHitResult;

public class BouncyBombItemEntity extends ThrowableItemProjectile {
    public BouncyBombItemEntity(EntityType<? extends ThrowableItemProjectile> pEntityType, Level pLevel) {
        super(pEntityType, pLevel);
    }

    @Override
    protected Item getDefaultItem() {
        return ItemInit.BOUNCY_BOMB.get();
    }

    public BouncyBombItemEntity(Level pLevel) {
        super(EntitiesInit.BOMB_ITEM_ENTITY.get(), pLevel);
    }

    public BouncyBombItemEntity(Level pLevel, LivingEntity livingEntity) {
        super(EntitiesInit.BOUNCY_BOMB_ITEM_ENTITY.get(), livingEntity, pLevel);
    }

    @Override
    protected void onHitBlock(BlockHitResult hitResult) {
        if (!this.level().isClientSide()) {
            this.level().broadcastEntityEvent(this, ((byte) 3));

            BlockPos hitPos = hitResult.getBlockPos();
            float explosionPower = 6.0f; // You can adjust the explosion power as needed

            this.level().explode(null, hitPos.getX(), hitPos.getY(), hitPos.getZ(), explosionPower, Level.ExplosionInteraction.TNT);

            super.onHitBlock(hitResult);
        }
    }}