>>“You have to shoot in Manual mode to really learn photography.”

To learn photography? Absolutely not. But you'll need it for flash photography - and to take over from your camera when the semi-auto modes aren't doing what you want.

It's a tool. Knowing it can make using your camera easier. For instance, I'm a landscape guy. I'm mostly in semi-auto (aperture priority and Auto-ISO), but I switch to full manual when it makes my life easier.

Do you need it right away? Nope - unless you're going to start on flash (trust me, manual is easier than guessing WTH auto mode is trying to do - and even once you get that dialed in in auto a minor change in scene lighting can change everything).

Also, pay attention to lens weight. If you're mostly looking for as deep a DoF as you can get, there's no reason to spend $$$ on a heavier, faster lens at that FL. Your shoulder will thank you. :-)