Most Helpful Girl
When I first started going to the gym I was so tired I could go to sleep when I got home. It was like that for a few weeks/months, then I got used to it. Also you should work out when you're healthy and fit. Especially 'cause you haven't done much cardio for 4 years. They say you need 24-48 hours rest between sessions. Hence why most lifters go for leg-arm-cardio repeat. That way your muscles and body can recover. Personally I wait for the muscle ache to die down, that way I know my muscles recovered and I can push them again.
But that's overall advice, you're free to do as you please.
Most Helpful Guy
You’ll get used to cardio in less than a week trust me bro