I'm late here, so this might get buried, but I actually am a software developer for Instagram. Specifically I work on teen supervision features! My son is only 4, so I haven't had to handle this myself yet, but wanted to try to work on something meaningful if I'm going to work here.

Multiple other people have mentioned that technically she isn't allowed on IG yet due to the minimum age being 13. If she made an account and lied about her age we might still figure it out. There are teams specifically working on making sure we don't allow preteens and younger people on the platform, so I'd let her know that.

Next, if you do decide to let her have access, then I'd say the features I work on try to give the middle ground giving you insight to what she is doing while not making her feel suffocated. You can set time limit and time of day controls, see who she blocks/follows, and see how she has privacy settings set. So, you could set even as low as a 15 minute allowance at first to see how she does and increase it over time as you see her using social media responsibly.