Is a TSH level of 0.7 normal? Does it matter that it's on the lower end of the range?

Level normal. Your TSH is normal. Although the normal range for TSH goes between 0.4 and 4.5, most people have TSH levels under 2. It does not matter that it is in the lower range of normal. If you have symptoms, it is not related to your thyroid.
Thyroid levels. Whereas blood tests can be helpful, just treating a blood test can be dangerous. A low end on the TSH could mean you have a slightly overactive thyroid. All the other thyroid levels should be checked and matched with your symptoms. Also check anti-thyroglobulin antibodies and anti-tpo.
Repeat. Do you have any symtoms of hyper thyroidism ? If yes, then repeat TSH after 6 weeks. At the same time discuss with your doctor to whether check thyroid anti-bodies and thyroid ultra sound ? For now, the TSH is within the reference range.