It's automatic and has 155K miles, battery is ~2 months old from Costco - interstate one.
Resting voltage of battery is 12.6-12.65V. It was running fine until past weekend and was parked for almost 4-5 days.
Today I went to start and it's not starting. While cranking battery light on the ODO stays on. Could it be an alternator or a starter? It does have fuel.
Thank you for any of your help.