In today’s active duty Army, you don’t get five years to be a butterbar. If you’re half-way competent, you’d make 1st Lt. within 18 to 30 months....otherwise you’re shown the door.
Reserves? There’s a little bit of lee way but not much. Again, making it to 1st Lt. shouldn’t be that much of a challenge unless you’re a total screw up.
...unless part of that time was enlisted.