My baby is 7 weeks old. She has begun to consistently roll on to her side to sleep when placed on her back. Should I be rolling her back on to her back due to her young age? Also does this count as 'signs of rolling', meaning I should stop swaddling her with her arms in?

Yes, this would count as “sign of rolling”.

Most babies are rolling by 4 to 5 months of age, but some roll early.
This is not something that needs to be stopped, but it is important to make the sleep environment as safe as is possible.
It is time to cease swaddling & transfer to cot, if she is still in bassinet.
Ensure that the cot mattress is firm & flat & there is nothing soft or loose in his cot.
Always continue to place baby on back to sleep.
Increasing tummy time when awake may also helpful.

Red Nose has the following information now that your baby is she starting to roll.

Give baby extra tummy time to play when awake and supervised as this helps baby to develop stronger neck and upper body muscles which in turn enables them to roll back over.
Make sure that baby is on a firm and well-fitting mattress that is flat (not tilted or elevated).
Make sure that baby’s face and head remains uncovered (do not use lambswool, doonas, pillows, cot bumpers or soft toys)

As babies grow and develop they become very active and learn to roll around the cot.
At this time, continue to put them on the back at the start of sleep time, but let them find their own position of comfort.
By this stage it is not necessary to wake during the night to turn baby over to the back position

Do not use any devices designed to keep baby in a particular sleep position.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over