Gelsomina, if you complete that training plan you'll definitely have the legs for a Whitney dayhike. Unfortunately, as others have mentioned, it's the altitude that stops many dayhikers. That 12,000-foot level - roughly Trail Camp - presents a wall to a fairly high percentage of folks dayhiking the mountain. And conditioning has little to no bearing on your susceptibility to be hit by AMS - many a marathoner has flamed out on Whitney due to not appreciating what 70% of sea level oxygen can do to your body, aerobic beast or not.

Dayhikers are more likely to be hit with AMS than overnighters who get that extra night's acclimation at roughly 12,000 feet. If you can, I would suggest spending those two nights prior to Whitney at Horseshoe Meadows campground (10,000 feet). It's about a 45-minute drive south of the Portal. Suggestion number two would be get a scrip for Diamox from your doctor and go on it 48 hours prior to your dayhike. Not the recommended doasege (for glaucoma), but 62.5 mg to 125 mg twice a day. Between solid acclimation and having Diamox in your system, you'll have the best chance of warding off AMS and making this a memorable experience and not a death march.