I’m 18 male 6’3 357lbs

I recently got NAFLD and I recently started walking I did a 10 min walk jusy starting out light so I don’t die lol but I checked my heart rate and it was 167bpm after the walk I don’t know if this is concerning or what I didn’t feel no chest pain or anything a little light headed but it is also 84° and I was in a hoodie and joggers was just wanting some opinion on it. Like if it dangerous for my heart to get like that while walking cause I’m really trying to lose weight but I feel like I’m at a wall. Any opinions/reassurance will help thanks.