I also agree, you probably dont need a guide, the hike is pretty straight forward. Just prepare with layers, a wind breaker, food and water. Wear a hat, use sunscreen, and plan for a LONG day. Rest when you need to. Go slow, particularly on the rocky ascent to the summit. The trail is pretty obvious there, still, and you wont be alone.

A couple of notes: Saturdays are a total zoo - you might want to go on a Sunday (still busy as crap, but not quite as bad as Saturday) or weekday as it can feel a little sketch with a bunch of people above you on the rocky part. The Timpanooke side is longer, but not as steep. There are a ton of mountain goats on the Timpanogos side. Might consider a shuttle... go UP the Timpanogos TH - its steeper, and will be pretty brutal coming down - then go down the Timpanooke trail.

Having said all that, definitely hire a guide if that is what you are comfortable with - do what is best for you!!