。
She's an attention seeker.
Literal
She [topic-は] attention-wanting person is.
目立ちたがり屋 (めだちたがりや) is a compound: 目立つ ('to stand out') + たがり (from ~がる, showing desire) + 屋 (や, 'person type'). The ~がり屋 suffix creates personality labels: 恥ずかしがり屋 ('shy person'), 寂しがり屋 ('lonely type').