How secure is my rstudio setup?

I am creating an Amazon EC2 instance to host an rstudio service. This service will be available through a reverse proxy through Apache server on port 443. I am a statistician and I am pretty unfamiliar with security on the net but I would be working with some pretty sensitive data on the rstudio service.

I've set up the firewall to only open ports 22 and 443 for ssh and https respectively. I've also only allowed my personal ip address to access the instance.

How secure is this setup really? Would a potential third party be able to pretend to use my ip address and access the server?