My son was sleeping the same at her age... He was almost 4 mos old and only able to stay up for 1H...
We increased A when he swiched to 4H EASY...just follow your dd's cues for now...
Andrew is a very good sleeper to this day, 2H naps at 7 mos old...and has been sleeping through the night since he was 8 weeks old, thanks to the DF...
Enjoy it, even though you will have some milestones that will disrupt sleep once in a while, such as rolling over, sitting up...but they all pass...
Like us, some kids just LOVEEE to sleep...good for them, helps them grow well!!!