Development till now is normal...so dont worry... Make your baby to sit with support with precautions... She should sit without support after 8months of age... Thumb sucking is normal...

Your baby is able to roll at 5 months means she achieved her mile stone for that age Babies will be able to sit with out support by 8-9 th month. Your baby now 7 months will be able to sit by next month.Babies crawl forward in 10 months. Give some bright color toys balls rattle rings hang them over her cradle or bed. She will play with them . Look into her face give smiling expressions ,make coo sounds ,sing rhymes,repetitive phrases . try to speak to her play with her. Tell her about mummy day grandpa etc if she feel lonely and insecure she keep her thumb in mouth

Babies at 7 months sit with support and roll over

Hi! At 7month they can only sit with support. Encourage sitting with all safety precautions. Children are best learners, they learn and try new things themselves. Give child bright coloured toys and rattle toys etc You can try putting your hand at legs so that child pushes herself forward. Sucking thumb is normal, as she grows older they stop. Do not worry.