Many of us on the forum would suggest that with your clothes and tack you should weigh no more than 15% of the weight of the pony, so you'll need a pony of about 425kg to meet that rule. Tack and c.othes are surprisingly heavy!
As a taller person for a tiny pony, you will also need to be sure that you can fit into the saddle which will fit in the pony's back.
Weight wise I think a big Shetland could carry you but the saddle is possibly an issue.