You can speak, read and write common

Your size is medium 

You walking speed is normally 25ft 

You gain unarmoured ac equivalent to your constitution modifier

You can curl up into a ball adding +3 to your AC and meaning you cannot attack or cast spells that don't only require a verbal activation. In this form you can move up to 70ft in one movement in a straight line (dm interpretation) unaffected by rough terrain you cannot turn or brake until the end of your movement dealing 1d4 × (1/5 of movement done) bludgeoning damage to an enemy you roll into as part of your action and as a bonus action you can unfurl your body into its bipedal stance.

If you use this as an attack then the target needs to make a dex saving throw in comparison to you con + 12 

On a successful save the target dodges out of the way and takes half damage but you continue rolling either until you are stopped, hit another target or reach the end of your movement.

You gain tremor sense up to 70ft in your ball form

You age at a similar rate to humans, reach maturity at 18 and typically live to a unusual age between 80 and 100

You get a +1 to strength and a +2 to constitution 

You have disadvantage on stealth, sleight of hand and acrobatics checks