Op, by all means apply. A lot depends on your child's temperament. There are many families who foster successfully.
You could do respite care or short term care for a child who is younger than your child, if they are ok with it. You won't know until you're doing it. It might be fine, like child minding with your own child there. Or you could find your child struggles around children who are disoriented and unpredictable. You could get into a fairly cosy arrangement where a child with special needs spends a weekend with you once a month. That would probably be manageable.
An older child would be potentially hard, or any long term foster placement. Older children have no obligation to put up with a young child and they will be a powerful influence. They may say things that you would prefer your child not to hear without having any idea that it isn't within the realms of normal childhood experience. They may find your child annoying. It's difficult because any older sibling would feel the same at times, but you will probably feel protective of your child. Even if it works really well, that also backfires when they leave. Significant people coming and going is hard work to process emotionally.
I was in a family that fostered and I have fostered as an adult. As a child, I'm not sorry to have had the experience but it was very hard for one of my siblings. One foster child's relative was in prison for a heinous crime against a person we knew. Naturally the child had a different narrative about this and spoke it it often. We struggled with cognitive dissonance, hearing about this person and how wonderful they were, seeing their letters from prison stuck up on a bedroom wall in our home. It was an odd life and there was no support to help us think these things through.
Many children in foster children quite understandably need to be put first because they are in pain. Their attachment style can be exhausting. While that is a good opportunity to develop empathy, it is hard to accept that your parents are having to put another child first. And then another, and another. And there are endless appointments and visits that your child will have to fit around. I had a privileged childhood and this didn't destroy me by any means, but I'm just saying - it's not what I would want for my own children while they're small and vulnerable.
I also went through a horrendous grieving experience once when a child I really loved had to go. I missed them desperately - missed doing all the things that you do for an adored little brother. For some reason, I wasn't expecting that one to leave. I was so worried for them and I was all of ten years old. They eventually returned to our family years later, traumatized by their experiences in the interim. I felt helpless and furious and somehow responsible for it, as children do. Huge emotions for a teenager. You don't get to see fostered children again unless they've been taken into care again - it's like a death.
As an adult, I fostered before having children and now that I have my own, I cannot imagine the emotional chaos for my own children. But we do need foster families so do what's right for you.
Be aware that children who have been sexually abused may need supervision and social services may play down their history in their efforts to secure a placement. You're not always working with a system that has the resources to support you and they can drain your time and energy almost as much as the children. It's wonderful to help other children but do make sure you are your own child's advocate.
This reads badly but there are also upsides to realising your privilege and learning how to care about strangers as a way of life. I'm mentioning the negatives so you can be aware.