Before you make the jump review the guides and compare the parts I would also review the model info from [https://everymac.com/systems/apple/macbook-air/index-macbook-air.html|EveryMac - MacBook Air systems]
[https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs] the 2011 systems use a different blade SSD which means you’ll need to get a replacement that meets your needs.
Get an 8GB system for sure, as a 4GB system is too lean memory wise which tends to wear out the SSD.
You may want to run the numbers to review your costs, I’m sure you can find used systems which other than a worn battery will more that meet your needs for a lot less! A i7 with 8GB and 1 or 2TB SSD. I just snagged an Early 2013 for $240 as a Xmas gift for a 12yo I tutor.