Then I'd go with normal. Hard is probably too much on a first play through with an unfamiliar battle system, even if the game is very front loaded in terms of it's difficulty.
I mean, don't get me wrong, the battle system isn't all that complicated(hit an enemy's weakness, the character gets another turn, enemy hits your weakness, enemy gets another turn), but a lot of the battles are about the prep work beforehand(getting different personas with different skills to hit different weaknesses while trying not to get whacked by an enemy hitting yours) rather than fights being too hard.
To that end, the best advice I'd probably give you is to keep your main character's personas current. The party members you'll get only have their Persona's level, while the MC has his own level and then equips different Personas(these equipped Personas have their own level and earn their own experience). Since the MC's personas usually take 2.5x the amount of experience to level than the regular party member's do, it's easy to find yourself getting whalloped without knowing why when your party is lv25 and you're using a lv15 Persona.
Still, something like this is not something you'll probably have to worry about even in your first dozen hours of game, so just have fun.
Play on normal. Don't use a social link guide. Don't worry about mis-managing your time, just enjoy yourself.
Finally! Like others have said, take your time and enjoy the ride. You might feel overwhelmed with the rules of the world at first (juggling events, school, dungeons, all within a fixed calendar) but remember you can always be doing something productive with your time -- be it social linking with your bro, doing a part-time job, or just scarfing a beef bowl downtown.
Also, remember to take a matching persona with you on S. Links. For example, take a Magician arcana persona when you hang out with Yosuke. It'll help speed along the S. Link process. That's kind of an important thing that I'm not sure the game really stresses.
Anyway, I'm so excited for you to dive in! Keep us posted on your progress here or on twitter! Enjoy Dawgson~!
Welcome Dawg. Don't worry too much about difficulty, just take your time and enjoy the game. It'll be way easier to get full completion on your second play through.
Thanks <3