Unable to reach service with ingress-nginx

Question

I am really new to Kubernetes/minikube... I have to make service and hit "/first" and use ingress-nginx without ingress addon in minikube. Even though I have added to my YAML file ingressClassName: nginx spec field. I am unable to reach my service and I am getting 404 Not Found. With ingress addon it works perfectly.Any idea what am I doing wrong? Thank you for your time! My Yaml file with some changes:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx 
  rules:
  - http:
      paths:
      - path: /first
        pathType: Prefix
        backend:
          service:
            name: first
            port:
              number: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: first
spec:
  type: ClusterIP
  ports:
  - port: 8080
  selector:
    app: first
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: first
spec:
  replicas: 1
  selector:
    matchLabels:
      app: first
  template:
    metadata:
      labels:
        app: first
    spec:
      containers:
      - name: first
        image: myimage:latest 
        env:
        - name: MESSAGE
          value: "This is the first service"
        resources:
          limits:
            cpu: "200m"
            memory: "256Mi"
---
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: first-flask
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: first
  minReplicas: 1
  maxReplicas: 8
  targetCPUUtilizationPercentage: 80