A solid choice. Levelling as a PLD isn't actually all that bad. Lacking DPS was only really noticeable in certain circumstances eg. inability to comfortably AoE grind in any capacity (which is not the same as 'AoE tanking until stuff eventually dies'), but mono-e-mono you have the CD's and off-GCDs to pummel everything pretty quickly. Given you'll be enjoying instant dungeon queues, there's not much to worry about. If all else fails, you'll unlock provoke and any other PLD skills you can make use of as other tanks later whether you decide to main it or not, so it's always a decent way to start as a tank-minded player and easy-to-play as well.