Without the right I think your hand is significantly weakened by not leading trump 1st trick. Especially holding an ace. Even if the dealer had the right as well there's still a decent chance both your hearts walk for the point. By leading offsuit you're probably forcing yourself to use a trump to take your first trick if your AH doesn't walk. Now you're left with only 2 trump with still potentially 2 killers out there. You could lose them both then have no way of getting the lead back for your 2nd heart lead.
Obviously if you had the right it's a no brainer to lead it with an offsuit ace. But if for example you had

instead with the right you have the security of the power of the right if you lead

1st trick. Without the right you're potentially putting yourself in a spot of bother because it's risky to lead 1 of your 2 remaining trumps still needing 2 tricks.
A general rule I follow is the lower the trump the more important it is to lead trump. You have a pretty weak trump holding here especially considering you ordered up an ace. You did the right thing IMO
EDIT I now realise you weren't asking what suit to lead but what trump card.
I prefer to lead low trying to draw out the right. Leading the left is dangerous if S2 holds the right and the dealer has at least 2. They now have 2 guaranteed tricks and a guaranteed euchre if dealer holds 3. Even if they only hold 2 you're very likely relying on both hearts to walk. Whereas if you lead low and manage to draw out the right you're probably good for the point.