Are there any long-term studies on HRT safety

So, exactly as the title says...my Mum came to me begging to not go on HRT because it will permanently change my body (she doesn't know I've been on it for 4 days (🥳), and that that js the point), and that she says it isn't safe. Are there any studies I could send her which show the long term (25 years +) safety of it?