For one, you're still 11 years younger than me. Welcome to the dark side.
Get a big board, around 152cm is a good size for early planing in 15 knots for big guys.
Kite - most well established brands are good these days, around 14 - 15 sq m I would imagine.

When you get your lessons let the instructor best guide you on your choice of gear.

I garrantee you'll loose 20kg over summer because you'll be on the water all day and have no time to eat! (Another kiter told me this because he did)

My mate is 90kg and he uses the same kites as me. We're sort of light wind specialists.

We used to use 12m Switchblades and now we have 13m Crossbows.

So anything in the bow kite design around 12-14m will do for a kite.

Actually riding in light winds is an acquired skill. Most beginners (and most kiters) choke the kite by half stalling it (pulling the bar in too far for too long at the wrong time). You need to fly the kite with some speed then pull in the bar to convert the speed into power, then ease the bar out again. It's a feel thing and you can only learn it with practice.

The board is also critical to riding in light winds. A fairly big, flat twintip is the go to start with. My mate rides a 150 cm x 44cm Underground.

Flat is better for riding fast and in lighter winds. Too much rocker is slooooooow but good for carving and holding lots of power. Most people have too small boards.

I am a big fan of Underground kiteboards and Cardboards have been good too.

Surfboards are fun but it takes a fair amount of skill to manage the kite and the board at the same time. The fins and rocker of surfboards makes them a bit slow in lighter conditions.

Rule number one of kiting is learn to fly the kite first. Spend 2-3-4-5 times as much time getting good at flying the kite before you add the board. If you add the board too soon you will crash your kite a lot and get really pissed off.

BTW I'm 54, 20 years windsurfing, 10 years kiting. Kiting is too easy once you get it. The learning curve is steep to start with, levels off for post beginners, then gets steep once you try to do hard tricks. You don't need to do hard tricks to have fun.

Any of the Deltas. SB, Bandit, Rally etc and also consider a Rebel. Good low end, re-launch and upwind ability will make for happy days........

First off you need to take lessons!
There are a number of kite shops in Melbourne that should have suitable equipment for ya..
kitesurfdirect, kitepower, shq boardsports, kiterepublic, ralkiteboarding, gokite, katani..

That being said, you don't have to go bigger than 14m if the kite is a somewhat powerful bow. It just limits your top end (bigger kites have a smaller wind range, same for bigger boards), and in Melbourne you don't have to aim for 15 knots anyway. 15-20 knots, anything less and the wind is too fickle.
I weigh 90kgs, 14m Ocean Rodeo Rise, 136 x 41 board, 12-14kn on the beach is just enough to stay upwind, when I struggle to stay upwind rarely anyone can do either.
Surely that requires technique, but let it be 15-20kn and even a beginner on the same equipment should be fine.

So take lessons, take it easy at the beginning, ride slow and not overpowered, get a feeling for the board and footbalance, and always visualize the right stance (Don't bend at the waist!). When you do that, you will stay upwind shortly after the first 50m ride.